Condensed Consolidating Financial Information (Condensed Consolidating Balance Sheets) (Details) - USD ($) $ in Thousands |
Sep. 30, 2017 |
Dec. 31, 2016 |
Sep. 30, 2016 |
Dec. 31, 2015 |
Current assets |
|
|
|
|
Cash and cash equivalents |
$ 125,271
|
$ 1,275,875
|
$ 364,276
|
$ 112,974
|
Restricted Cash |
0
|
185,000
|
|
|
Accounts receivable—oil and natural gas |
180,106
|
136,761
|
|
|
Accounts receivable - related parties |
362
|
16
|
|
|
Accounts receivable - intercompany |
|
0
|
|
|
Prepaid expenses and other current assets |
5,666
|
3,135
|
|
|
Short-term derivative instruments |
35,332
|
3,488
|
|
|
Total current assets |
346,737
|
1,604,275
|
|
|
Property and equipment |
|
|
|
|
Oil and natural gas properties |
8,867,239
|
6,071,920
|
|
|
Other property and equipment |
84,225
|
68,986
|
|
|
Accumulated depletion, depreciation, amortization and impairment |
(4,043,879)
|
(3,789,780)
|
|
|
Property and equipment, net |
4,907,585
|
2,351,126
|
|
|
Other assets |
|
|
|
|
Equity investments and investments in subsidiaries |
279,282
|
243,920
|
|
|
Long-term derivative instruments |
6,409
|
5,696
|
|
|
Deferred tax asset |
4,692
|
4,692
|
|
|
Inventories |
13,908
|
4,504
|
|
|
Other assets |
18,985
|
8,932
|
|
|
Total other assets |
323,276
|
267,744
|
|
|
Total assets |
5,577,598
|
4,223,145
|
|
|
Current liabilities |
|
|
|
|
Accounts payable and accrued liabilities |
582,928
|
265,124
|
|
|
Accounts payable - intercompany |
0
|
0
|
|
|
Asset retirement obligation—current |
195
|
195
|
75
|
|
Derivative instruments |
29,130
|
119,219
|
|
|
Current maturities of long-term debt |
570
|
276
|
|
|
Total current liabilities |
612,823
|
384,814
|
|
|
Long-term derivative instrument |
19,712
|
26,759
|
|
|
Asset retirement obligation—long-term |
44,266
|
34,081
|
32,910
|
|
Long-term debt, net of current maturities |
1,958,136
|
1,593,599
|
|
|
Total liabilities |
2,634,937
|
2,039,253
|
|
|
Stockholders’ equity |
|
|
|
|
Common stock |
1,831
|
1,588
|
|
|
Paid-in capital |
4,413,623
|
3,946,442
|
|
|
Accumulated other comprehensive (loss) income |
(40,339)
|
(53,058)
|
|
|
Retained (deficit) earnings |
(1,432,454)
|
(1,711,080)
|
|
|
Total stockholders’ equity |
2,942,661
|
2,183,892
|
1,725,120
|
2,038,837
|
Total liabilities and stockholders’ equity |
5,577,598
|
4,223,145
|
|
|
Reportable Legal Entities | Parent |
|
|
|
|
Current assets |
|
|
|
|
Cash and cash equivalents |
89,095
|
1,273,882
|
363,279
|
112,494
|
Restricted Cash |
|
185,000
|
|
|
Accounts receivable—oil and natural gas |
126,746
|
137,087
|
|
|
Accounts receivable - related parties |
362
|
16
|
|
|
Accounts receivable - intercompany |
514,187
|
449,517
|
|
|
Prepaid expenses and other current assets |
5,486
|
3,135
|
|
|
Short-term derivative instruments |
35,332
|
3,488
|
|
|
Total current assets |
771,208
|
2,052,125
|
|
|
Property and equipment |
|
|
|
|
Oil and natural gas properties |
6,371,324
|
5,655,125
|
|
|
Other property and equipment |
84,182
|
68,943
|
|
|
Accumulated depletion, depreciation, amortization and impairment |
(4,043,843)
|
(3,789,746)
|
|
|
Property and equipment, net |
2,411,663
|
1,934,322
|
|
|
Other assets |
|
|
|
|
Equity investments and investments in subsidiaries |
2,262,011
|
236,327
|
|
|
Long-term derivative instruments |
6,409
|
5,696
|
|
|
Deferred tax asset |
4,692
|
4,692
|
|
|
Inventories |
9,438
|
3,095
|
|
|
Other assets |
10,561
|
8,932
|
|
|
Total other assets |
2,293,111
|
258,742
|
|
|
Total assets |
5,475,982
|
4,245,189
|
|
|
Current liabilities |
|
|
|
|
Accounts payable and accrued liabilities |
430,195
|
255,966
|
|
|
Accounts payable - intercompany |
57,927
|
31,202
|
|
|
Asset retirement obligation—current |
195
|
195
|
|
|
Derivative instruments |
29,130
|
119,219
|
|
|
Current maturities of long-term debt |
570
|
276
|
|
|
Total current liabilities |
518,017
|
406,858
|
|
|
Long-term derivative instrument |
19,712
|
26,759
|
|
|
Asset retirement obligation—long-term |
37,456
|
34,081
|
|
|
Long-term debt, net of current maturities |
1,958,136
|
1,593,599
|
|
|
Total liabilities |
2,533,321
|
2,061,297
|
|
|
Stockholders’ equity |
|
|
|
|
Common stock |
1,831
|
1,588
|
|
|
Paid-in capital |
4,413,623
|
3,946,442
|
|
|
Accumulated other comprehensive (loss) income |
(40,339)
|
(53,058)
|
|
|
Retained (deficit) earnings |
(1,432,454)
|
(1,711,080)
|
|
|
Total stockholders’ equity |
2,942,661
|
2,183,892
|
|
|
Total liabilities and stockholders’ equity |
5,475,982
|
4,245,189
|
|
|
Reportable Legal Entities | Guarantors |
|
|
|
|
Current assets |
|
|
|
|
Cash and cash equivalents |
36,175
|
1,993
|
996
|
479
|
Restricted Cash |
|
0
|
|
|
Accounts receivable—oil and natural gas |
53,360
|
37,496
|
|
|
Accounts receivable - related parties |
0
|
0
|
|
|
Accounts receivable - intercompany |
57,927
|
1,151
|
|
|
Prepaid expenses and other current assets |
180
|
0
|
|
|
Short-term derivative instruments |
0
|
0
|
|
|
Total current assets |
147,642
|
40,640
|
|
|
Property and equipment |
|
|
|
|
Oil and natural gas properties |
2,496,644
|
417,524
|
|
|
Other property and equipment |
43
|
43
|
|
|
Accumulated depletion, depreciation, amortization and impairment |
(36)
|
(34)
|
|
|
Property and equipment, net |
2,496,651
|
417,533
|
|
|
Other assets |
|
|
|
|
Equity investments and investments in subsidiaries |
70,375
|
33,590
|
|
|
Long-term derivative instruments |
0
|
0
|
|
|
Deferred tax asset |
0
|
0
|
|
|
Inventories |
4,470
|
1,409
|
|
|
Other assets |
8,424
|
0
|
|
|
Total other assets |
83,269
|
34,999
|
|
|
Total assets |
2,727,562
|
493,172
|
|
|
Current liabilities |
|
|
|
|
Accounts payable and accrued liabilities |
152,733
|
9,158
|
|
|
Accounts payable - intercompany |
514,060
|
457,163
|
|
|
Asset retirement obligation—current |
0
|
0
|
|
|
Derivative instruments |
0
|
0
|
|
|
Current maturities of long-term debt |
0
|
0
|
|
|
Total current liabilities |
666,793
|
466,321
|
|
|
Long-term derivative instrument |
0
|
0
|
|
|
Asset retirement obligation—long-term |
6,810
|
0
|
|
|
Long-term debt, net of current maturities |
0
|
0
|
|
|
Total liabilities |
673,603
|
466,321
|
|
|
Stockholders’ equity |
|
|
|
|
Common stock |
0
|
0
|
|
|
Paid-in capital |
1,905,599
|
33,822
|
|
|
Accumulated other comprehensive (loss) income |
0
|
0
|
|
|
Retained (deficit) earnings |
148,360
|
(6,971)
|
|
|
Total stockholders’ equity |
2,053,959
|
26,851
|
|
|
Total liabilities and stockholders’ equity |
2,727,562
|
493,172
|
|
|
Reportable Legal Entities | Non-Guarantor |
|
|
|
|
Current assets |
|
|
|
|
Cash and cash equivalents |
1
|
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 |
1
|
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 |
58,674
|
45,213
|
|
|
Long-term derivative instruments |
0
|
0
|
|
|
Deferred tax asset |
0
|
0
|
|
|
Inventories |
0
|
0
|
|
|
Other assets |
0
|
0
|
|
|
Total other assets |
58,674
|
45,213
|
|
|
Total assets |
58,675
|
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 |
258,871
|
257,026
|
|
|
Accumulated other comprehensive (loss) income |
(38,443)
|
(50,931)
|
|
|
Retained (deficit) earnings |
(161,880)
|
(161,008)
|
|
|
Total stockholders’ equity |
58,548
|
45,087
|
|
|
Total liabilities and stockholders’ equity |
58,675
|
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 |
(572,114)
|
(450,668)
|
|
|
Prepaid expenses and other current assets |
0
|
0
|
|
|
Short-term derivative instruments |
0
|
0
|
|
|
Total current assets |
(572,114)
|
(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 |
(2,111,778)
|
(71,210)
|
|
|
Long-term derivative instruments |
0
|
0
|
|
|
Deferred tax asset |
0
|
0
|
|
|
Inventories |
0
|
0
|
|
|
Other assets |
0
|
0
|
|
|
Total other assets |
(2,111,778)
|
(71,210)
|
|
|
Total assets |
(2,684,621)
|
(560,429)
|
|
|
Current liabilities |
|
|
|
|
Accounts payable and accrued liabilities |
0
|
0
|
|
|
Accounts payable - intercompany |
(572,114)
|
(488,491)
|
|
|
Asset retirement obligation—current |
0
|
0
|
|
|
Derivative instruments |
0
|
0
|
|
|
Current maturities of long-term debt |
0
|
0
|
|
|
Total current liabilities |
(572,114)
|
(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 |
(572,114)
|
(488,491)
|
|
|
Stockholders’ equity |
|
|
|
|
Common stock |
0
|
0
|
|
|
Paid-in capital |
(2,164,470)
|
(290,848)
|
|
|
Accumulated other comprehensive (loss) income |
38,443
|
50,931
|
|
|
Retained (deficit) earnings |
13,520
|
167,979
|
|
|
Total stockholders’ equity |
(2,112,507)
|
(71,938)
|
|
|
Total liabilities and stockholders’ equity |
$ (2,684,621)
|
$ (560,429)
|
|
|