CONDENSED CONSOLIDATING FINANCIAL INFORMATION (Balance Sheets) (Details) - USD ($) $ in Thousands |
Jun. 30, 2020 |
Mar. 31, 2020 |
Dec. 31, 2019 |
Jun. 30, 2019 |
Mar. 31, 2019 |
Dec. 31, 2018 |
Current assets: |
|
|
|
|
|
|
Cash and cash equivalents |
$ 2,817
|
|
$ 6,060
|
|
|
|
Accounts receivable - oil and natural gas sales |
65,645
|
|
121,210
|
|
|
|
Accounts receivable - joint interest and other |
19,389
|
|
47,975
|
|
|
|
Accounts receivable - intercompany |
0
|
|
0
|
|
|
|
Prepaid expenses and other current assets |
10,862
|
|
4,431
|
|
|
|
Short-term derivative instruments |
53,188
|
|
126,201
|
|
|
|
Total current assets |
151,901
|
|
305,877
|
|
|
|
Property and equipment: |
|
|
|
|
|
|
Oil and natural gas properties |
10,730,992
|
|
10,595,735
|
|
|
|
Other property and equipment |
96,838
|
|
96,719
|
|
|
|
Accumulated depletion, depreciation, amortization and impairment |
(8,457,464)
|
|
(7,228,660)
|
|
|
|
Property and equipment, net |
2,370,366
|
|
3,463,794
|
|
|
|
Other assets: |
|
|
|
|
|
|
Equity investments and investments in subsidiaries |
13,052
|
|
32,044
|
|
|
|
Long-term derivative instruments |
4,298
|
|
563
|
|
|
|
Deferred tax asset |
0
|
|
7,563
|
|
|
|
Operating lease assets |
3,640
|
|
14,168
|
|
|
|
Operating lease assets—related parties |
0
|
|
43,270
|
|
|
|
Other assets |
37,000
|
|
15,540
|
|
|
|
Total other assets |
57,990
|
|
113,148
|
|
|
|
Total assets |
2,580,257
|
|
3,882,819
|
|
|
|
Current liabilities: |
|
|
|
|
|
|
Accounts payable and accrued liabilities |
315,575
|
|
415,218
|
|
|
|
Accounts payable - intercompany |
0
|
|
0
|
|
|
|
Short-term derivative instruments |
8,540
|
|
303
|
|
|
|
Current portion of operating lease liabilities |
3,356
|
|
13,826
|
|
|
|
Current portion of operating lease liabilities—related parties |
0
|
|
21,220
|
|
|
|
Current maturities of long-term debt |
649
|
|
631
|
|
|
|
Total current liabilities |
328,120
|
|
451,198
|
|
|
|
Long-term derivative instruments |
45,615
|
|
53,135
|
|
|
|
Asset retirement obligation - long-term |
61,371
|
|
60,355
|
|
|
|
Uncertain tax position liability |
3,209
|
|
3,127
|
|
|
|
Non-current operating lease liabilities |
284
|
|
342
|
|
|
|
Non-current operating lease liabilities—related parties |
0
|
|
22,050
|
|
|
|
Long-term debt, net of current maturities |
1,910,318
|
|
1,978,020
|
|
|
|
Total liabilities |
2,348,917
|
|
2,568,227
|
|
|
|
Stockholders’ equity: |
|
|
|
|
|
|
Common stock |
1,601
|
|
1,597
|
|
|
|
Paid-in capital |
4,211,062
|
|
4,207,554
|
|
|
|
Accumulated other comprehensive loss |
(54,991)
|
|
(46,833)
|
|
|
|
Accumulated deficit |
(3,926,332)
|
|
(2,847,726)
|
|
|
|
Total stockholders’ equity |
231,340
|
$ 784,049
|
1,314,592
|
$ 3,607,408
|
$ 3,368,266
|
$ 3,327,768
|
Total liabilities and stockholders’ equity |
2,580,257
|
|
3,882,819
|
|
|
|
Reportable legal entities | Parent |
|
|
|
|
|
|
Current assets: |
|
|
|
|
|
|
Cash and cash equivalents |
823
|
|
2,768
|
|
|
|
Accounts receivable - oil and natural gas sales |
860
|
|
859
|
|
|
|
Accounts receivable - joint interest and other |
2,949
|
|
5,279
|
|
|
|
Accounts receivable - intercompany |
1,482,102
|
|
1,065,593
|
|
|
|
Prepaid expenses and other current assets |
10,781
|
|
4,047
|
|
|
|
Short-term derivative instruments |
53,188
|
|
126,201
|
|
|
|
Total current assets |
1,550,703
|
|
1,204,747
|
|
|
|
Property and equipment: |
|
|
|
|
|
|
Oil and natural gas properties |
1,247,631
|
|
1,314,933
|
|
|
|
Other property and equipment |
92,768
|
|
92,650
|
|
|
|
Accumulated depletion, depreciation, amortization and impairment |
(1,423,539)
|
|
(1,418,888)
|
|
|
|
Property and equipment, net |
(83,140)
|
|
(11,305)
|
|
|
|
Other assets: |
|
|
|
|
|
|
Equity investments and investments in subsidiaries |
1,930,479
|
|
3,064,503
|
|
|
|
Long-term derivative instruments |
|
|
563
|
|
|
|
Deferred tax asset |
|
|
7,563
|
|
|
|
Operating lease assets |
3,640
|
|
14,168
|
|
|
|
Operating lease assets—related parties |
|
|
43,270
|
|
|
|
Other assets |
29,216
|
|
10,026
|
|
|
|
Total other assets |
1,967,633
|
|
3,140,093
|
|
|
|
Total assets |
3,435,196
|
|
4,333,535
|
|
|
|
Current liabilities: |
|
|
|
|
|
|
Accounts payable and accrued liabilities |
46,085
|
|
48,006
|
|
|
|
Accounts payable - intercompany |
1,185,800
|
|
878,283
|
|
|
|
Short-term derivative instruments |
8,540
|
|
303
|
|
|
|
Current portion of operating lease liabilities |
3,356
|
|
13,826
|
|
|
|
Current portion of operating lease liabilities—related parties |
|
|
21,220
|
|
|
|
Current maturities of long-term debt |
649
|
|
631
|
|
|
|
Total current liabilities |
1,244,430
|
|
962,269
|
|
|
|
Long-term derivative instruments |
45,615
|
|
53,135
|
|
|
|
Asset retirement obligation - long-term |
0
|
|
0
|
|
|
|
Uncertain tax position liability |
3,209
|
|
3,127
|
|
|
|
Non-current operating lease liabilities |
284
|
|
342
|
|
|
|
Non-current operating lease liabilities—related parties |
|
|
22,050
|
|
|
|
Long-term debt, net of current maturities |
1,910,318
|
|
1,978,020
|
|
|
|
Total liabilities |
3,203,856
|
|
3,018,943
|
|
|
|
Stockholders’ equity: |
|
|
|
|
|
|
Common stock |
1,601
|
|
1,597
|
|
|
|
Paid-in capital |
4,211,062
|
|
4,207,554
|
|
|
|
Accumulated other comprehensive loss |
(54,991)
|
|
(46,833)
|
|
|
|
Accumulated deficit |
(3,926,332)
|
|
(2,847,726)
|
|
|
|
Total stockholders’ equity |
231,340
|
|
1,314,592
|
|
|
|
Total liabilities and stockholders’ equity |
3,435,196
|
|
4,333,535
|
|
|
|
Reportable legal entities | Guarantors |
|
|
|
|
|
|
Current assets: |
|
|
|
|
|
|
Cash and cash equivalents |
1,748
|
|
3,097
|
|
|
|
Accounts receivable - oil and natural gas sales |
64,785
|
|
120,351
|
|
|
|
Accounts receivable - joint interest and other |
16,440
|
|
42,696
|
|
|
|
Accounts receivable - intercompany |
1,150,631
|
|
843,223
|
|
|
|
Prepaid expenses and other current assets |
5
|
|
308
|
|
|
|
Short-term derivative instruments |
0
|
|
0
|
|
|
|
Total current assets |
1,233,609
|
|
1,009,675
|
|
|
|
Property and equipment: |
|
|
|
|
|
|
Oil and natural gas properties |
9,478,228
|
|
9,273,681
|
|
|
|
Other property and equipment |
51
|
|
50
|
|
|
|
Accumulated depletion, depreciation, amortization and impairment |
(7,032,075)
|
|
(5,808,254)
|
|
|
|
Property and equipment, net |
2,446,204
|
|
3,465,477
|
|
|
|
Other assets: |
|
|
|
|
|
|
Equity investments and investments in subsidiaries |
6,332
|
|
6,332
|
|
|
|
Long-term derivative instruments |
|
|
0
|
|
|
|
Deferred tax asset |
|
|
0
|
|
|
|
Operating lease assets |
0
|
|
0
|
|
|
|
Operating lease assets—related parties |
|
|
0
|
|
|
|
Other assets |
7,784
|
|
5,514
|
|
|
|
Total other assets |
14,116
|
|
11,846
|
|
|
|
Total assets |
3,693,929
|
|
4,486,998
|
|
|
|
Current liabilities: |
|
|
|
|
|
|
Accounts payable and accrued liabilities |
269,490
|
|
367,088
|
|
|
|
Accounts payable - intercompany |
1,442,144
|
|
1,026,249
|
|
|
|
Short-term derivative instruments |
0
|
|
0
|
|
|
|
Current portion of operating lease liabilities |
0
|
|
0
|
|
|
|
Current portion of operating lease liabilities—related parties |
|
|
0
|
|
|
|
Current maturities of long-term debt |
0
|
|
0
|
|
|
|
Total current liabilities |
1,711,634
|
|
1,393,337
|
|
|
|
Long-term derivative instruments |
0
|
|
0
|
|
|
|
Asset retirement obligation - long-term |
61,371
|
|
58,322
|
|
|
|
Uncertain tax position liability |
0
|
|
0
|
|
|
|
Non-current operating lease liabilities |
0
|
|
0
|
|
|
|
Non-current operating lease liabilities—related parties |
|
|
0
|
|
|
|
Long-term debt, net of current maturities |
0
|
|
0
|
|
|
|
Total liabilities |
1,773,005
|
|
1,451,659
|
|
|
|
Stockholders’ equity: |
|
|
|
|
|
|
Common stock |
0
|
|
0
|
|
|
|
Paid-in capital |
4,171,409
|
|
4,171,408
|
|
|
|
Accumulated other comprehensive loss |
0
|
|
0
|
|
|
|
Accumulated deficit |
(2,250,485)
|
|
(1,136,069)
|
|
|
|
Total stockholders’ equity |
1,920,924
|
|
3,035,339
|
|
|
|
Total liabilities and stockholders’ equity |
3,693,929
|
|
4,486,998
|
|
|
|
Reportable legal entities | Non-Guarantors |
|
|
|
|
|
|
Current assets: |
|
|
|
|
|
|
Cash and cash equivalents |
246
|
|
195
|
|
|
|
Accounts receivable - oil and natural gas sales |
0
|
|
0
|
|
|
|
Accounts receivable - joint interest and other |
0
|
|
0
|
|
|
|
Accounts receivable - intercompany |
0
|
|
0
|
|
|
|
Prepaid expenses and other current assets |
76
|
|
76
|
|
|
|
Short-term derivative instruments |
0
|
|
0
|
|
|
|
Total current assets |
322
|
|
271
|
|
|
|
Property and equipment: |
|
|
|
|
|
|
Oil and natural gas properties |
5,862
|
|
7,850
|
|
|
|
Other property and equipment |
4,019
|
|
4,019
|
|
|
|
Accumulated depletion, depreciation, amortization and impairment |
(1,850)
|
|
(1,518)
|
|
|
|
Property and equipment, net |
8,031
|
|
10,351
|
|
|
|
Other assets: |
|
|
|
|
|
|
Equity investments and investments in subsidiaries |
13,013
|
|
21,000
|
|
|
|
Long-term derivative instruments |
|
|
0
|
|
|
|
Deferred tax asset |
|
|
0
|
|
|
|
Operating lease assets |
0
|
|
0
|
|
|
|
Operating lease assets—related parties |
|
|
0
|
|
|
|
Other assets |
0
|
|
0
|
|
|
|
Total other assets |
13,013
|
|
21,000
|
|
|
|
Total assets |
21,366
|
|
31,622
|
|
|
|
Current liabilities: |
|
|
|
|
|
|
Accounts payable and accrued liabilities |
0
|
|
124
|
|
|
|
Accounts payable - intercompany |
4,789
|
|
4,285
|
|
|
|
Short-term derivative instruments |
0
|
|
0
|
|
|
|
Current portion of operating lease liabilities |
0
|
|
0
|
|
|
|
Current portion of operating lease liabilities—related parties |
|
|
0
|
|
|
|
Current maturities of long-term debt |
0
|
|
0
|
|
|
|
Total current liabilities |
4,789
|
|
4,409
|
|
|
|
Long-term derivative instruments |
0
|
|
0
|
|
|
|
Asset retirement obligation - long-term |
0
|
|
2,033
|
|
|
|
Uncertain tax position liability |
0
|
|
0
|
|
|
|
Non-current operating lease liabilities |
0
|
|
0
|
|
|
|
Non-current operating lease liabilities—related parties |
|
|
0
|
|
|
|
Long-term debt, net of current maturities |
0
|
|
0
|
|
|
|
Total liabilities |
4,789
|
|
6,442
|
|
|
|
Stockholders’ equity: |
|
|
|
|
|
|
Common stock |
0
|
|
0
|
|
|
|
Paid-in capital |
267,559
|
|
267,557
|
|
|
|
Accumulated other comprehensive loss |
(52,562)
|
|
(44,763)
|
|
|
|
Accumulated deficit |
(198,420)
|
|
(197,614)
|
|
|
|
Total stockholders’ equity |
16,577
|
|
25,180
|
|
|
|
Total liabilities and stockholders’ equity |
21,366
|
|
31,622
|
|
|
|
Eliminations |
|
|
|
|
|
|
Current assets: |
|
|
|
|
|
|
Cash and cash equivalents |
0
|
|
0
|
|
|
|
Accounts receivable - oil and natural gas sales |
0
|
|
0
|
|
|
|
Accounts receivable - joint interest and other |
0
|
|
0
|
|
|
|
Accounts receivable - intercompany |
(2,632,733)
|
|
(1,908,816)
|
|
|
|
Prepaid expenses and other current assets |
0
|
|
0
|
|
|
|
Short-term derivative instruments |
0
|
|
0
|
|
|
|
Total current assets |
(2,632,733)
|
|
(1,908,816)
|
|
|
|
Property and equipment: |
|
|
|
|
|
|
Oil and natural gas properties |
(729)
|
|
(729)
|
|
|
|
Other property and equipment |
0
|
|
0
|
|
|
|
Accumulated depletion, depreciation, amortization and impairment |
0
|
|
0
|
|
|
|
Property and equipment, net |
(729)
|
|
(729)
|
|
|
|
Other assets: |
|
|
|
|
|
|
Equity investments and investments in subsidiaries |
(1,936,772)
|
|
(3,059,791)
|
|
|
|
Long-term derivative instruments |
|
|
0
|
|
|
|
Deferred tax asset |
|
|
0
|
|
|
|
Operating lease assets |
0
|
|
0
|
|
|
|
Operating lease assets—related parties |
|
|
0
|
|
|
|
Other assets |
0
|
|
0
|
|
|
|
Total other assets |
(1,936,772)
|
|
(3,059,791)
|
|
|
|
Total assets |
(4,570,234)
|
|
(4,969,336)
|
|
|
|
Current liabilities: |
|
|
|
|
|
|
Accounts payable and accrued liabilities |
0
|
|
0
|
|
|
|
Accounts payable - intercompany |
(2,632,733)
|
|
(1,908,817)
|
|
|
|
Short-term derivative instruments |
0
|
|
0
|
|
|
|
Current portion of operating lease liabilities |
0
|
|
0
|
|
|
|
Current portion of operating lease liabilities—related parties |
|
|
0
|
|
|
|
Current maturities of long-term debt |
0
|
|
0
|
|
|
|
Total current liabilities |
(2,632,733)
|
|
(1,908,817)
|
|
|
|
Long-term derivative instruments |
0
|
|
0
|
|
|
|
Asset retirement obligation - long-term |
0
|
|
0
|
|
|
|
Uncertain tax position liability |
0
|
|
0
|
|
|
|
Non-current operating lease liabilities |
0
|
|
0
|
|
|
|
Non-current operating lease liabilities—related parties |
|
|
0
|
|
|
|
Long-term debt, net of current maturities |
0
|
|
0
|
|
|
|
Total liabilities |
(2,632,733)
|
|
(1,908,817)
|
|
|
|
Stockholders’ equity: |
|
|
|
|
|
|
Common stock |
0
|
|
0
|
|
|
|
Paid-in capital |
(4,438,968)
|
|
(4,438,965)
|
|
|
|
Accumulated other comprehensive loss |
52,562
|
|
44,763
|
|
|
|
Accumulated deficit |
2,448,905
|
|
1,333,683
|
|
|
|
Total stockholders’ equity |
(1,937,501)
|
|
(3,060,519)
|
|
|
|
Total liabilities and stockholders’ equity |
$ (4,570,234)
|
|
$ (4,969,336)
|
|
|
|