Condensed Consolidating Financial Information - Balance Sheets (Details) - USD ($)
|
Dec. 31, 2018 |
Dec. 31, 2017 |
Dec. 31, 2016 |
Dec. 31, 2015 |
Current assets: |
|
|
|
|
Cash and cash equivalents |
$ 52,297,000
|
$ 99,557,000
|
|
|
Accounts receivable—oil and natural gas sales |
210,200,000
|
146,773,000
|
|
|
Accounts receivable - joint interest and other |
22,497,000
|
35,440,000
|
|
|
Accounts receivable - intercompany |
0
|
0
|
|
|
Prepaid expenses and other current assets |
10,607,000
|
4,912,000
|
|
|
Short-term derivative instruments - asset |
21,352,000
|
78,847,000
|
|
|
Total current assets |
316,953,000
|
365,529,000
|
|
|
Property and equipment: |
|
|
|
|
Oil and natural gas properties, full-cost accounting |
10,026,836,000
|
9,169,156,000
|
|
|
Other property and equipment |
92,667,000
|
86,754,000
|
|
|
Accumulated depletion, depreciation, amortization and impairment |
(4,640,098,000)
|
(4,153,733,000)
|
|
|
Property and equipment, net |
5,479,405,000
|
5,102,177,000
|
|
|
Other assets: |
|
|
|
|
Equity investments and investments in subsidiaries |
236,121,000
|
302,112,000
|
|
|
Long-term derivative instruments |
0
|
8,685,000
|
|
|
Deferred tax asset |
0
|
1,208,000
|
|
|
Inventories |
4,754,000
|
8,227,000
|
|
|
Other assets |
13,803,000
|
19,814,000
|
|
|
Total other assets |
254,678,000
|
340,046,000
|
|
|
Total assets |
6,051,036,000
|
5,807,752,000
|
|
|
Current liabilities: |
|
|
|
|
Accounts payable and accrued liabilities |
518,380,000
|
553,609,000
|
|
|
Accounts payable - intercompany |
0
|
0
|
|
|
Asset retirement obligation—current |
0
|
120,000
|
|
|
Short-term derivative instruments |
20,401,000
|
32,534,000
|
|
|
Current maturities of long-term debt |
651,000
|
622,000
|
|
|
Total current liabilities |
539,432,000
|
586,885,000
|
|
|
Long-term derivative instruments |
13,992,000
|
2,989,000
|
|
|
Asset retirement obligation—long-term |
79,952,000
|
74,980,000
|
|
|
Deferred tax liability |
3,127,000
|
0
|
|
|
Other non-current liabilities |
0
|
2,963,000
|
|
|
Long-term debt, net of current maturities |
2,086,765,000
|
2,038,321,000
|
|
|
Total liabilities |
2,723,268,000
|
2,706,138,000
|
|
|
Stockholders’ equity: |
|
|
|
|
Common stock |
1,630,000
|
1,831,000
|
|
|
Paid-in capital |
4,227,532,000
|
4,416,250,000
|
|
|
Accumulated other comprehensive loss |
(56,026,000)
|
(40,539,000)
|
|
|
(Accumulated deficit) retained earnings |
(845,368,000)
|
(1,275,928,000)
|
|
|
Total stockholders’ equity |
3,327,768,000
|
3,101,614,000
|
$ 2,183,892,000
|
$ 2,038,837,000
|
Total liabilities and stockholders’ equity |
6,051,036,000
|
5,807,752,000
|
|
|
Eliminations |
|
|
|
|
Current assets: |
|
|
|
|
Cash and cash equivalents |
0
|
0
|
|
|
Accounts receivable—oil and natural gas sales |
|
0
|
|
|
Accounts receivable - joint interest and other |
0
|
0
|
|
|
Accounts receivable - intercompany |
(991,097,000)
|
(617,813,000)
|
|
|
Prepaid expenses and other current assets |
0
|
0
|
|
|
Short-term derivative instruments - asset |
0
|
0
|
|
|
Total current assets |
(991,097,000)
|
(617,813,000)
|
|
|
Property and equipment: |
|
|
|
|
Oil and natural gas properties, full-cost accounting |
(729,000)
|
(729,000)
|
|
|
Other property and equipment |
0
|
0
|
|
|
Accumulated depletion, depreciation, amortization and impairment |
0
|
0
|
|
|
Property and equipment, net |
(729,000)
|
(729,000)
|
|
|
Other assets: |
|
|
|
|
Equity investments and investments in subsidiaries |
(2,665,126,000)
|
(2,194,848,000)
|
|
|
Long-term derivative instruments |
|
0
|
|
|
Deferred tax asset |
|
0
|
|
|
Inventories |
0
|
0
|
|
|
Other assets |
1,000
|
0
|
|
|
Total other assets |
(2,665,125,000)
|
(2,194,848,000)
|
|
|
Total assets |
(3,656,951,000)
|
(2,813,390,000)
|
|
|
Current liabilities: |
|
|
|
|
Accounts payable and accrued liabilities |
|
(1,000)
|
|
|
Accounts payable - intercompany |
(991,097,000)
|
(617,813,000)
|
|
|
Asset retirement obligation—current |
|
0
|
|
|
Short-term derivative instruments |
0
|
0
|
|
|
Current maturities of long-term debt |
0
|
0
|
|
|
Total current liabilities |
(991,097,000)
|
(617,814,000)
|
|
|
Long-term derivative instruments |
0
|
0
|
|
|
Asset retirement obligation—long-term |
0
|
0
|
|
|
Deferred tax liability |
0
|
|
|
|
Other non-current liabilities |
|
0
|
|
|
Long-term debt, net of current maturities |
0
|
0
|
|
|
Total liabilities |
(991,097,000)
|
(617,814,000)
|
|
|
Stockholders’ equity: |
|
|
|
|
Common stock |
0
|
0
|
|
|
Paid-in capital |
(2,177,224,000)
|
(2,174,905,000)
|
|
|
Accumulated other comprehensive loss |
53,783,000
|
38,593,000
|
|
|
(Accumulated deficit) retained earnings |
(542,413,000)
|
(59,264,000)
|
|
|
Total stockholders’ equity |
(2,665,854,000)
|
(2,195,576,000)
|
|
|
Total liabilities and stockholders’ equity |
(3,656,951,000)
|
(2,813,390,000)
|
|
|
Parent |
|
|
|
|
Current assets: |
|
|
|
|
Cash and cash equivalents |
25,585,000
|
67,908,000
|
|
|
Accounts receivable—oil and natural gas sales |
146,075,000
|
112,686,000
|
|
|
Accounts receivable - joint interest and other |
16,212,000
|
15,435,000
|
|
|
Accounts receivable - intercompany |
671,633,000
|
554,439,000
|
|
|
Prepaid expenses and other current assets |
8,433,000
|
4,719,000
|
|
|
Short-term derivative instruments - asset |
21,352,000
|
78,847,000
|
|
|
Total current assets |
889,290,000
|
834,034,000
|
|
|
Property and equipment: |
|
|
|
|
Oil and natural gas properties, full-cost accounting |
7,044,550,000
|
6,562,147,000
|
|
|
Other property and equipment |
91,916,000
|
86,711,000
|
|
|
Accumulated depletion, depreciation, amortization and impairment |
(4,640,059,000)
|
(4,153,696,000)
|
|
|
Property and equipment, net |
2,496,407,000
|
2,495,162,000
|
|
|
Other assets: |
|
|
|
|
Equity investments and investments in subsidiaries |
2,856,988,000
|
2,361,575,000
|
|
|
Long-term derivative instruments |
|
8,685,000
|
|
|
Deferred tax asset |
|
1,208,000
|
|
|
Inventories |
3,620,000
|
5,816,000
|
|
|
Other assets |
12,624,000
|
12,483,000
|
|
|
Total other assets |
2,873,232,000
|
2,389,767,000
|
|
|
Total assets |
6,258,929,000
|
5,718,963,000
|
|
|
Current liabilities: |
|
|
|
|
Accounts payable and accrued liabilities |
419,107,000
|
416,249,000
|
|
|
Accounts payable - intercompany |
320,259,000
|
63,373,000
|
|
|
Asset retirement obligation—current |
|
120,000
|
|
|
Short-term derivative instruments |
20,401,000
|
32,534,000
|
|
|
Current maturities of long-term debt |
651,000
|
622,000
|
|
|
Total current liabilities |
760,418,000
|
512,898,000
|
|
|
Long-term derivative instruments |
13,992,000
|
2,989,000
|
|
|
Asset retirement obligation—long-term |
66,859,000
|
63,141,000
|
|
|
Deferred tax liability |
3,127,000
|
|
|
|
Other non-current liabilities |
|
0
|
|
|
Long-term debt, net of current maturities |
2,086,765,000
|
2,038,321,000
|
|
|
Total liabilities |
2,931,161,000
|
2,617,349,000
|
|
|
Stockholders’ equity: |
|
|
|
|
Common stock |
1,630,000
|
1,831,000
|
|
|
Paid-in capital |
4,227,532,000
|
4,416,250,000
|
|
|
Accumulated other comprehensive loss |
(56,026,000)
|
(40,539,000)
|
|
|
(Accumulated deficit) retained earnings |
(845,368,000)
|
(1,275,928,000)
|
|
|
Total stockholders’ equity |
3,327,768,000
|
3,101,614,000
|
|
|
Total liabilities and stockholders’ equity |
6,258,929,000
|
5,718,963,000
|
|
|
Guarantors |
|
|
|
|
Current assets: |
|
|
|
|
Cash and cash equivalents |
26,711,000
|
31,649,000
|
|
|
Accounts receivable—oil and natural gas sales |
64,125,000
|
34,087,000
|
|
|
Accounts receivable - joint interest and other |
6,285,000
|
20,005,000
|
|
|
Accounts receivable - intercompany |
319,464,000
|
63,374,000
|
|
|
Prepaid expenses and other current assets |
2,174,000
|
193,000
|
|
|
Short-term derivative instruments - asset |
0
|
0
|
|
|
Total current assets |
418,759,000
|
149,308,000
|
|
|
Property and equipment: |
|
|
|
|
Oil and natural gas properties, full-cost accounting |
2,983,015,000
|
2,607,738,000
|
|
|
Other property and equipment |
751,000
|
43,000
|
|
|
Accumulated depletion, depreciation, amortization and impairment |
(39,000)
|
(37,000)
|
|
|
Property and equipment, net |
2,983,727,000
|
2,607,744,000
|
|
|
Other assets: |
|
|
|
|
Equity investments and investments in subsidiaries |
0
|
77,744,000
|
|
|
Long-term derivative instruments |
|
0
|
|
|
Deferred tax asset |
|
0
|
|
|
Inventories |
1,134,000
|
2,411,000
|
|
|
Other assets |
1,178,000
|
7,331,000
|
|
|
Total other assets |
2,312,000
|
87,486,000
|
|
|
Total assets |
3,404,798,000
|
2,844,538,000
|
|
|
Current liabilities: |
|
|
|
|
Accounts payable and accrued liabilities |
99,273,000
|
137,361,000
|
|
|
Accounts payable - intercompany |
670,708,000
|
554,313,000
|
|
|
Asset retirement obligation—current |
|
0
|
|
|
Short-term derivative instruments |
0
|
0
|
|
|
Current maturities of long-term debt |
0
|
0
|
|
|
Total current liabilities |
769,981,000
|
691,674,000
|
|
|
Long-term derivative instruments |
0
|
0
|
|
|
Asset retirement obligation—long-term |
13,093,000
|
11,839,000
|
|
|
Deferred tax liability |
0
|
|
|
|
Other non-current liabilities |
|
2,963,000
|
|
|
Long-term debt, net of current maturities |
0
|
0
|
|
|
Total liabilities |
783,074,000
|
706,476,000
|
|
|
Stockholders’ equity: |
|
|
|
|
Common stock |
0
|
0
|
|
|
Paid-in capital |
1,915,598,000
|
1,915,598,000
|
|
|
Accumulated other comprehensive loss |
0
|
0
|
|
|
(Accumulated deficit) retained earnings |
706,126,000
|
222,464,000
|
|
|
Total stockholders’ equity |
2,621,724,000
|
2,138,062,000
|
|
|
Total liabilities and stockholders’ equity |
3,404,798,000
|
2,844,538,000
|
|
|
Non-Guarantor |
|
|
|
|
Current assets: |
|
|
|
|
Cash and cash equivalents |
1,000
|
0
|
|
|
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 |
0
|
0
|
|
|
Short-term derivative instruments - asset |
0
|
0
|
|
|
Total current assets |
1,000
|
|
|
|
Property and equipment: |
|
|
|
|
Oil and natural gas properties, full-cost accounting |
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 |
44,259,000
|
57,641,000
|
|
|
Long-term derivative instruments |
|
0
|
|
|
Deferred tax asset |
|
0
|
|
|
Inventories |
0
|
0
|
|
|
Other assets |
0
|
0
|
|
|
Total other assets |
44,259,000
|
57,641,000
|
|
|
Total assets |
44,260,000
|
57,641,000
|
|
|
Current liabilities: |
|
|
|
|
Accounts payable and accrued liabilities |
0
|
0
|
|
|
Accounts payable - intercompany |
130,000
|
127,000
|
|
|
Asset retirement obligation—current |
|
0
|
|
|
Short-term derivative instruments |
0
|
0
|
|
|
Current maturities of long-term debt |
0
|
0
|
|
|
Total current liabilities |
130,000
|
127,000
|
|
|
Long-term derivative instruments |
0
|
0
|
|
|
Asset retirement obligation—long-term |
0
|
0
|
|
|
Deferred tax liability |
0
|
|
|
|
Other non-current liabilities |
|
0
|
|
|
Long-term debt, net of current maturities |
0
|
0
|
|
|
Total liabilities |
130,000
|
127,000
|
|
|
Stockholders’ equity: |
|
|
|
|
Common stock |
0
|
0
|
|
|
Paid-in capital |
261,626,000
|
259,307,000
|
|
|
Accumulated other comprehensive loss |
(53,783,000)
|
(38,593,000)
|
|
|
(Accumulated deficit) retained earnings |
(163,713,000)
|
(163,200,000)
|
|
|
Total stockholders’ equity |
44,130,000
|
57,514,000
|
|
|
Total liabilities and stockholders’ equity |
$ 44,260,000
|
$ 57,641,000
|
|
|