Condensed Consolidating Financial Information (Condensed Consolidating Balance Sheets) (Details) - USD ($) $ in Thousands |
Mar. 31, 2017 |
Dec. 31, 2016 |
Mar. 31, 2016 |
Dec. 31, 2015 |
Current assets: |
|
|
|
|
Cash and cash equivalents |
$ 102,485
|
$ 1,275,875
|
$ 454,377
|
$ 112,974
|
Restricted Cash |
0
|
185,000
|
|
|
Accounts receivable—oil and gas |
158,154
|
136,761
|
|
|
Accounts receivable - related parties |
39
|
16
|
|
|
Accounts receivable - intercompany |
|
0
|
|
|
Prepaid expenses and other current assets |
16,005
|
7,639
|
|
|
Short-term derivative instruments |
18,925
|
3,488
|
|
|
Total current assets |
295,608
|
1,608,779
|
|
|
Property and equipment: |
|
|
|
|
Oil and natural gas properties |
8,146,321
|
6,071,920
|
|
|
Other property and equipment |
75,107
|
68,986
|
|
|
Accumulated depletion, depreciation, amortization and impairment |
(3,855,629)
|
(3,789,780)
|
|
|
Property and equipment, net |
4,365,799
|
2,351,126
|
|
|
Other assets: |
|
|
|
|
Equity investments and investments in subsidiaries |
251,370
|
243,920
|
|
|
Long-term derivative instruments |
23,515
|
5,696
|
|
|
Deferred tax asset |
4,692
|
4,692
|
|
|
Other assets |
12,945
|
8,932
|
|
|
Total other assets |
292,522
|
263,240
|
|
|
Total assets |
4,953,929
|
4,223,145
|
|
|
Current liabilities: |
|
|
|
|
Accounts payable and accrued liabilities |
406,139
|
265,124
|
|
|
Accounts payable - intercompany |
0
|
0
|
|
|
Asset retirement obligation—current |
195
|
195
|
75
|
|
Derivative instruments |
67,179
|
119,219
|
|
|
Current maturities of long-term debt |
452
|
276
|
|
|
Total current liabilities |
473,965
|
384,814
|
|
|
Long-term derivative instrument |
5,259
|
26,759
|
|
|
Asset retirement obligation—long-term |
41,142
|
34,081
|
28,471
|
|
Long-term debt, net of current maturities |
1,631,809
|
1,593,599
|
|
|
Total liabilities |
2,152,175
|
2,039,253
|
|
|
Stockholders’ equity: |
|
|
|
|
Common stock |
1,828
|
1,588
|
|
|
Paid-in capital |
4,408,236
|
3,946,442
|
|
|
Accumulated other comprehensive (loss) income |
(51,685)
|
(53,058)
|
|
|
Retained (deficit) earnings |
(1,556,625)
|
(1,711,080)
|
|
|
Total stockholders’ equity |
2,801,754
|
2,183,892
|
2,220,789
|
2,038,837
|
Total liabilities and stockholders’ equity |
4,953,929
|
4,223,145
|
|
|
Reportable Legal Entities | Parent |
|
|
|
|
Current assets: |
|
|
|
|
Cash and cash equivalents |
71,934
|
1,273,882
|
453,743
|
112,494
|
Restricted Cash |
|
185,000
|
|
|
Accounts receivable—oil and gas |
106,008
|
137,087
|
|
|
Accounts receivable - related parties |
39
|
16
|
|
|
Accounts receivable - intercompany |
447,275
|
449,517
|
|
|
Prepaid expenses and other current assets |
12,330
|
6,230
|
|
|
Short-term derivative instruments |
18,925
|
3,488
|
|
|
Total current assets |
656,511
|
2,055,220
|
|
|
Property and equipment: |
|
|
|
|
Oil and natural gas properties |
5,869,066
|
5,655,125
|
|
|
Other property and equipment |
75,064
|
68,943
|
|
|
Accumulated depletion, depreciation, amortization and impairment |
(3,855,594)
|
(3,789,746)
|
|
|
Property and equipment, net |
2,088,536
|
1,934,322
|
|
|
Other assets: |
|
|
|
|
Equity investments and investments in subsidiaries |
2,120,462
|
236,327
|
|
|
Long-term derivative instruments |
23,515
|
5,696
|
|
|
Deferred tax asset |
4,692
|
4,692
|
|
|
Other assets |
8,765
|
8,932
|
|
|
Total other assets |
2,157,434
|
255,647
|
|
|
Total assets |
4,902,481
|
4,245,189
|
|
|
Current liabilities: |
|
|
|
|
Accounts payable and accrued liabilities |
326,175
|
255,966
|
|
|
Accounts payable - intercompany |
35,005
|
31,202
|
|
|
Asset retirement obligation—current |
195
|
195
|
|
|
Derivative instruments |
67,179
|
119,219
|
|
|
Current maturities of long-term debt |
452
|
276
|
|
|
Total current liabilities |
429,006
|
406,858
|
|
|
Long-term derivative instrument |
5,259
|
26,759
|
|
|
Asset retirement obligation—long-term |
34,653
|
34,081
|
|
|
Long-term debt, net of current maturities |
1,631,809
|
1,593,599
|
|
|
Total liabilities |
2,100,727
|
2,061,297
|
|
|
Stockholders’ equity: |
|
|
|
|
Common stock |
1,828
|
1,588
|
|
|
Paid-in capital |
4,408,236
|
3,946,442
|
|
|
Accumulated other comprehensive (loss) income |
(51,685)
|
(53,058)
|
|
|
Retained (deficit) earnings |
(1,556,625)
|
(1,711,080)
|
|
|
Total stockholders’ equity |
2,801,754
|
2,183,892
|
|
|
Total liabilities and stockholders’ equity |
4,902,481
|
4,245,189
|
|
|
Reportable Legal Entities | Guarantors |
|
|
|
|
Current assets: |
|
|
|
|
Cash and cash equivalents |
30,550
|
1,993
|
634
|
479
|
Restricted Cash |
|
0
|
|
|
Accounts receivable—oil and gas |
52,146
|
37,496
|
|
|
Accounts receivable - related parties |
0
|
0
|
|
|
Accounts receivable - intercompany |
35,434
|
1,151
|
|
|
Prepaid expenses and other current assets |
3,675
|
1,409
|
|
|
Short-term derivative instruments |
0
|
0
|
|
|
Total current assets |
121,805
|
42,049
|
|
|
Property and equipment: |
|
|
|
|
Oil and natural gas properties |
2,277,984
|
417,524
|
|
|
Other property and equipment |
43
|
43
|
|
|
Accumulated depletion, depreciation, amortization and impairment |
(35)
|
(34)
|
|
|
Property and equipment, net |
2,277,992
|
417,533
|
|
|
Other assets: |
|
|
|
|
Equity investments and investments in subsidiaries |
40,661
|
33,590
|
|
|
Long-term derivative instruments |
0
|
0
|
|
|
Deferred tax asset |
0
|
0
|
|
|
Other assets |
4,180
|
0
|
|
|
Total other assets |
44,841
|
33,590
|
|
|
Total assets |
2,444,638
|
493,172
|
|
|
Current liabilities: |
|
|
|
|
Accounts payable and accrued liabilities |
79,964
|
9,158
|
|
|
Accounts payable - intercompany |
447,577
|
457,163
|
|
|
Asset retirement obligation—current |
0
|
0
|
|
|
Derivative instruments |
0
|
0
|
|
|
Current maturities of long-term debt |
0
|
0
|
|
|
Total current liabilities |
527,541
|
466,321
|
|
|
Long-term derivative instrument |
0
|
0
|
|
|
Asset retirement obligation—long-term |
6,489
|
0
|
|
|
Long-term debt, net of current maturities |
0
|
0
|
|
|
Total liabilities |
534,030
|
466,321
|
|
|
Stockholders’ equity: |
|
|
|
|
Common stock |
0
|
0
|
|
|
Paid-in capital |
1,872,598
|
33,822
|
|
|
Accumulated other comprehensive (loss) income |
0
|
0
|
|
|
Retained (deficit) earnings |
38,010
|
(6,971)
|
|
|
Total stockholders’ equity |
1,910,608
|
26,851
|
|
|
Total liabilities and stockholders’ equity |
2,444,638
|
493,172
|
|
|
Reportable Legal Entities | Non-Guarantor |
|
|
|
|
Current assets: |
|
|
|
|
Cash and cash equivalents |
1
|
0
|
0
|
1
|
Restricted Cash |
|
0
|
|
|
Accounts receivable—oil and 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 |
46,838
|
45,213
|
|
|
Long-term derivative instruments |
0
|
0
|
|
|
Deferred tax asset |
0
|
0
|
|
|
Other assets |
0
|
0
|
|
|
Total other assets |
46,838
|
45,213
|
|
|
Total assets |
46,839
|
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 |
257,700
|
257,026
|
|
|
Accumulated other comprehensive (loss) income |
(49,613)
|
(50,931)
|
|
|
Retained (deficit) earnings |
(161,375)
|
(161,008)
|
|
|
Total stockholders’ equity |
46,712
|
45,087
|
|
|
Total liabilities and stockholders’ equity |
46,839
|
45,213
|
|
|
Eliminations |
|
|
|
|
Current assets: |
|
|
|
|
Cash and cash equivalents |
0
|
0
|
$ 0
|
$ 0
|
Restricted Cash |
|
0
|
|
|
Accounts receivable—oil and gas |
|
(37,822)
|
|
|
Accounts receivable - related parties |
0
|
0
|
|
|
Accounts receivable - intercompany |
(482,709)
|
(450,668)
|
|
|
Prepaid expenses and other current assets |
0
|
0
|
|
|
Short-term derivative instruments |
0
|
0
|
|
|
Total current assets |
(482,709)
|
(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 |
(1,956,591)
|
(71,210)
|
|
|
Long-term derivative instruments |
0
|
0
|
|
|
Deferred tax asset |
0
|
0
|
|
|
Other assets |
0
|
0
|
|
|
Total other assets |
(1,956,591)
|
(71,210)
|
|
|
Total assets |
(2,440,029)
|
(560,429)
|
|
|
Current liabilities: |
|
|
|
|
Accounts payable and accrued liabilities |
0
|
0
|
|
|
Accounts payable - intercompany |
(482,709)
|
(488,491)
|
|
|
Asset retirement obligation—current |
0
|
0
|
|
|
Derivative instruments |
0
|
0
|
|
|
Current maturities of long-term debt |
0
|
0
|
|
|
Total current liabilities |
(482,709)
|
(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 |
(482,709)
|
(488,491)
|
|
|
Stockholders’ equity: |
|
|
|
|
Common stock |
0
|
0
|
|
|
Paid-in capital |
(2,130,298)
|
(290,848)
|
|
|
Accumulated other comprehensive (loss) income |
49,613
|
50,931
|
|
|
Retained (deficit) earnings |
123,365
|
167,979
|
|
|
Total stockholders’ equity |
(1,957,320)
|
(71,938)
|
|
|
Total liabilities and stockholders’ equity |
$ (2,440,029)
|
$ (560,429)
|
|
|