Condensed Consolidating Financial Information (Condensed Consolidating Balance Sheets) (Details) - USD ($) $ in Thousands |
Jun. 30, 2017 |
Dec. 31, 2016 |
Jun. 30, 2016 |
Dec. 31, 2015 |
Current assets: |
|
|
|
|
Cash and cash equivalents |
$ 117,555
|
$ 1,275,875
|
$ 396,437
|
$ 112,974
|
Restricted Cash |
0
|
185,000
|
|
|
Accounts receivable—oil and natural gas |
164,154
|
136,761
|
|
|
Accounts receivable - related parties |
185
|
16
|
|
|
Accounts receivable - intercompany |
|
0
|
|
|
Prepaid expenses and other current assets |
4,279
|
3,135
|
|
|
Short-term derivative instruments |
46,416
|
3,488
|
|
|
Total current assets |
332,589
|
1,604,275
|
|
|
Property and equipment: |
|
|
|
|
Oil and natural gas properties |
8,500,790
|
6,071,920
|
|
|
Other property and equipment |
79,521
|
68,986
|
|
|
Accumulated depletion, depreciation, amortization and impairment |
(3,937,656)
|
(3,789,780)
|
|
|
Property and equipment, net |
4,642,655
|
2,351,126
|
|
|
Other assets: |
|
|
|
|
Equity investments and investments in subsidiaries |
256,265
|
243,920
|
|
|
Long-term derivative instruments |
19,761
|
5,696
|
|
|
Deferred tax asset |
4,692
|
4,692
|
|
|
Inventories |
19,303
|
4,504
|
|
|
Other assets |
18,890
|
8,932
|
|
|
Total other assets |
318,911
|
267,744
|
|
|
Total assets |
5,294,155
|
4,223,145
|
|
|
Current liabilities: |
|
|
|
|
Accounts payable and accrued liabilities |
495,734
|
265,124
|
|
|
Accounts payable - intercompany |
0
|
0
|
|
|
Asset retirement obligation—current |
195
|
195
|
75
|
|
Derivative instruments |
28,106
|
119,219
|
|
|
Current maturities of long-term debt |
595
|
276
|
|
|
Total current liabilities |
524,630
|
384,814
|
|
|
Long-term derivative instrument |
8,198
|
26,759
|
|
|
Asset retirement obligation—long-term |
43,934
|
34,081
|
29,993
|
|
Long-term debt, net of current maturities |
1,802,554
|
1,593,599
|
|
|
Total liabilities |
2,379,316
|
2,039,253
|
|
|
Stockholders’ equity: |
|
|
|
|
Common stock |
1,828
|
1,588
|
|
|
Paid-in capital |
4,410,871
|
3,946,442
|
|
|
Accumulated other comprehensive (loss) income |
(47,171)
|
(53,058)
|
|
|
Retained (deficit) earnings |
(1,450,689)
|
(1,711,080)
|
|
|
Total stockholders’ equity |
2,914,839
|
2,183,892
|
1,883,440
|
2,038,837
|
Total liabilities and stockholders’ equity |
5,294,155
|
4,223,145
|
|
|
Reportable Legal Entities | Parent |
|
|
|
|
Current assets: |
|
|
|
|
Cash and cash equivalents |
72,062
|
1,273,882
|
395,703
|
112,494
|
Restricted Cash |
|
185,000
|
|
|
Accounts receivable—oil and natural gas |
121,565
|
137,087
|
|
|
Accounts receivable - related parties |
185
|
16
|
|
|
Accounts receivable - intercompany |
459,503
|
449,517
|
|
|
Prepaid expenses and other current assets |
4,113
|
3,135
|
|
|
Short-term derivative instruments |
46,416
|
3,488
|
|
|
Total current assets |
703,844
|
2,052,125
|
|
|
Property and equipment: |
|
|
|
|
Oil and natural gas properties |
6,142,757
|
5,655,125
|
|
|
Other property and equipment |
79,478
|
68,943
|
|
|
Accumulated depletion, depreciation, amortization and impairment |
(3,937,621)
|
(3,789,746)
|
|
|
Property and equipment, net |
2,284,614
|
1,934,322
|
|
|
Other assets: |
|
|
|
|
Equity investments and investments in subsidiaries |
2,179,931
|
236,327
|
|
|
Long-term derivative instruments |
19,761
|
5,696
|
|
|
Deferred tax asset |
4,692
|
4,692
|
|
|
Inventories |
13,591
|
3,095
|
|
|
Other assets |
10,834
|
8,932
|
|
|
Total other assets |
2,228,809
|
258,742
|
|
|
Total assets |
5,217,267
|
4,245,189
|
|
|
Current liabilities: |
|
|
|
|
Accounts payable and accrued liabilities |
385,908
|
255,966
|
|
|
Accounts payable - intercompany |
39,564
|
31,202
|
|
|
Asset retirement obligation—current |
195
|
195
|
|
|
Derivative instruments |
28,106
|
119,219
|
|
|
Current maturities of long-term debt |
595
|
276
|
|
|
Total current liabilities |
454,368
|
406,858
|
|
|
Long-term derivative instrument |
8,198
|
26,759
|
|
|
Asset retirement obligation—long-term |
37,308
|
34,081
|
|
|
Long-term debt, net of current maturities |
1,802,554
|
1,593,599
|
|
|
Total liabilities |
2,302,428
|
2,061,297
|
|
|
Stockholders’ equity: |
|
|
|
|
Common stock |
1,828
|
1,588
|
|
|
Paid-in capital |
4,410,871
|
3,946,442
|
|
|
Accumulated other comprehensive (loss) income |
(47,171)
|
(53,058)
|
|
|
Retained (deficit) earnings |
(1,450,689)
|
(1,711,080)
|
|
|
Total stockholders’ equity |
2,914,839
|
2,183,892
|
|
|
Total liabilities and stockholders’ equity |
5,217,267
|
4,245,189
|
|
|
Reportable Legal Entities | Guarantors |
|
|
|
|
Current assets: |
|
|
|
|
Cash and cash equivalents |
45,493
|
1,993
|
733
|
479
|
Restricted Cash |
|
0
|
|
|
Accounts receivable—oil and natural gas |
42,589
|
37,496
|
|
|
Accounts receivable - related parties |
0
|
0
|
|
|
Accounts receivable - intercompany |
45,749
|
1,151
|
|
|
Prepaid expenses and other current assets |
166
|
0
|
|
|
Short-term derivative instruments |
0
|
0
|
|
|
Total current assets |
133,997
|
40,640
|
|
|
Property and equipment: |
|
|
|
|
Oil and natural gas properties |
2,358,762
|
417,524
|
|
|
Other property and equipment |
43
|
43
|
|
|
Accumulated depletion, depreciation, amortization and impairment |
(35)
|
(34)
|
|
|
Property and equipment, net |
2,358,770
|
417,533
|
|
|
Other assets: |
|
|
|
|
Equity investments and investments in subsidiaries |
52,946
|
33,590
|
|
|
Long-term derivative instruments |
0
|
0
|
|
|
Deferred tax asset |
0
|
0
|
|
|
Inventories |
5,712
|
1,409
|
|
|
Other assets |
8,056
|
0
|
|
|
Total other assets |
66,714
|
34,999
|
|
|
Total assets |
2,559,481
|
493,172
|
|
|
Current liabilities: |
|
|
|
|
Accounts payable and accrued liabilities |
109,826
|
9,158
|
|
|
Accounts payable - intercompany |
465,561
|
457,163
|
|
|
Asset retirement obligation—current |
0
|
0
|
|
|
Derivative instruments |
0
|
0
|
|
|
Current maturities of long-term debt |
0
|
0
|
|
|
Total current liabilities |
575,387
|
466,321
|
|
|
Long-term derivative instrument |
0
|
0
|
|
|
Asset retirement obligation—long-term |
6,626
|
0
|
|
|
Long-term debt, net of current maturities |
0
|
0
|
|
|
Total liabilities |
582,013
|
466,321
|
|
|
Stockholders’ equity: |
|
|
|
|
Common stock |
0
|
0
|
|
|
Paid-in capital |
1,885,598
|
33,822
|
|
|
Accumulated other comprehensive (loss) income |
0
|
0
|
|
|
Retained (deficit) earnings |
91,870
|
(6,971)
|
|
|
Total stockholders’ equity |
1,977,468
|
26,851
|
|
|
Total liabilities and stockholders’ equity |
2,559,481
|
493,172
|
|
|
Reportable Legal Entities | Non-Guarantor |
|
|
|
|
Current assets: |
|
|
|
|
Cash and cash equivalents |
0
|
0
|
1
|
1
|
Restricted Cash |
|
0
|
|
|
Accounts receivable—oil and natural gas |
0
|
0
|
|
|
Accounts receivable - related parties |
0
|
0
|
|
|
Accounts receivable - intercompany |
0
|
0
|
|
|
Prepaid expenses and other current assets |
0
|
0
|
|
|
Short-term derivative instruments |
0
|
0
|
|
|
Total current assets |
0
|
0
|
|
|
Property and equipment: |
|
|
|
|
Oil and natural gas properties |
0
|
0
|
|
|
Other property and equipment |
0
|
0
|
|
|
Accumulated depletion, depreciation, amortization and impairment |
0
|
0
|
|
|
Property and equipment, net |
0
|
0
|
|
|
Other assets: |
|
|
|
|
Equity investments and investments in subsidiaries |
51,605
|
45,213
|
|
|
Long-term derivative instruments |
0
|
0
|
|
|
Deferred tax asset |
0
|
0
|
|
|
Inventories |
0
|
0
|
|
|
Other assets |
0
|
0
|
|
|
Total other assets |
51,605
|
45,213
|
|
|
Total assets |
51,605
|
45,213
|
|
|
Current liabilities: |
|
|
|
|
Accounts payable and accrued liabilities |
0
|
0
|
|
|
Accounts payable - intercompany |
127
|
126
|
|
|
Asset retirement obligation—current |
0
|
0
|
|
|
Derivative instruments |
0
|
0
|
|
|
Current maturities of long-term debt |
0
|
0
|
|
|
Total current liabilities |
127
|
126
|
|
|
Long-term derivative instrument |
0
|
0
|
|
|
Asset retirement obligation—long-term |
0
|
0
|
|
|
Long-term debt, net of current maturities |
0
|
0
|
|
|
Total liabilities |
127
|
126
|
|
|
Stockholders’ equity: |
|
|
|
|
Common stock |
0
|
0
|
|
|
Paid-in capital |
258,178
|
257,026
|
|
|
Accumulated other comprehensive (loss) income |
(45,117)
|
(50,931)
|
|
|
Retained (deficit) earnings |
(161,583)
|
(161,008)
|
|
|
Total stockholders’ equity |
51,478
|
45,087
|
|
|
Total liabilities and stockholders’ equity |
51,605
|
45,213
|
|
|
Eliminations |
|
|
|
|
Current assets: |
|
|
|
|
Cash and cash equivalents |
0
|
0
|
$ 0
|
$ 0
|
Restricted Cash |
|
0
|
|
|
Accounts receivable—oil and natural gas |
0
|
(37,822)
|
|
|
Accounts receivable - related parties |
0
|
0
|
|
|
Accounts receivable - intercompany |
(505,252)
|
(450,668)
|
|
|
Prepaid expenses and other current assets |
0
|
0
|
|
|
Short-term derivative instruments |
0
|
0
|
|
|
Total current assets |
(505,252)
|
(488,490)
|
|
|
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 |
(2,028,217)
|
(71,210)
|
|
|
Long-term derivative instruments |
0
|
0
|
|
|
Deferred tax asset |
0
|
0
|
|
|
Inventories |
0
|
0
|
|
|
Other assets |
0
|
0
|
|
|
Total other assets |
(2,028,217)
|
(71,210)
|
|
|
Total assets |
(2,534,198)
|
(560,429)
|
|
|
Current liabilities: |
|
|
|
|
Accounts payable and accrued liabilities |
0
|
0
|
|
|
Accounts payable - intercompany |
(505,252)
|
(488,491)
|
|
|
Asset retirement obligation—current |
0
|
0
|
|
|
Derivative instruments |
0
|
0
|
|
|
Current maturities of long-term debt |
0
|
0
|
|
|
Total current liabilities |
(505,252)
|
(488,491)
|
|
|
Long-term derivative instrument |
0
|
0
|
|
|
Asset retirement obligation—long-term |
0
|
0
|
|
|
Long-term debt, net of current maturities |
0
|
0
|
|
|
Total liabilities |
(505,252)
|
(488,491)
|
|
|
Stockholders’ equity: |
|
|
|
|
Common stock |
0
|
0
|
|
|
Paid-in capital |
(2,143,776)
|
(290,848)
|
|
|
Accumulated other comprehensive (loss) income |
45,117
|
50,931
|
|
|
Retained (deficit) earnings |
69,713
|
167,979
|
|
|
Total stockholders’ equity |
(2,028,946)
|
(71,938)
|
|
|
Total liabilities and stockholders’ equity |
$ (2,534,198)
|
$ (560,429)
|
|
|