Fresh Start Accounting - Balance sheet effects (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Oct. 21, 2016	Oct. 20, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
CURRENT ASSETS:
Cash and cash equivalents	$ 76,838	$ 76,540	$ 76,540
Accounts receivable:
Oil and gas sales	36,988	33,895
Joint interest billing	4,281	4,739
Other	2,456	26
Other current assets	3,326	5,677
Total current assets	123,889	120,877
PROPERTY AND EQUIPMENT:
Oil and gas properties, on the basis of full-cost accounting		619,220
Other property and equipment	6,339	6,210
Less accumulated depreciation, depletion, amortization and impairment	(12,974)
Net property and equipment	631,595	625,430
OTHER NONCURRENT ASSETS	5,455	4,951
TOTAL	760,939	751,258
CURRENT LIABILITIES:
Accounts payable	2,521	10,294
Accrued liabilities	53,731	49,824
Total current liabilities	56,252	60,118
ASSET RETIREMENT OBLIGATIONS	14,200	13,983
OTHER LONG-TERM LIABILITIES	614	128,676
COMMITMENTS AND CONTINGENCIES
STOCKHOLDERS' EQUITY (DEFICIT):
Preferred stock
Warrants		37,329
Common stock	250	247
Additional paid-in-capital	514,305	510,905
Retained deficit	9,930
Total stockholders' equity (deficit)	561,814	548,481
TOTAL	$ 760,939	751,258
Reorganization Adjustments
CURRENT ASSETS:
Cash and cash equivalents		(197,990)
Accounts receivable:
Other current assets		(2,748)
Total current assets		(200,738)
PROPERTY AND EQUIPMENT:
OTHER NONCURRENT ASSETS		1,250
TOTAL		(199,488)
CURRENT LIABILITIES:
Accrued liabilities		(15,416)
Debt classified as current less unamortized debt issuance costs		(249,384)
Total current liabilities		(264,800)
OTHER LONG-TERM LIABILITIES		128,059
LIABILITIES SUBJECT TO COMPROMISE (Note 2)		(1,882,187)
COMMITMENTS AND CONTINGENCIES
STOCKHOLDERS' EQUITY (DEFICIT):
Warrants		37,329
Common stock		247
Treasury stock		3,134
Additional paid-in-capital		510,905
Retained deficit		2,159,221
Total stockholders' equity (deficit)		1,819,440
TOTAL		(199,488)
Fresh Start Adjustments
CURRENT ASSETS:
Cash and cash equivalents		76,540
PROPERTY AND EQUIPMENT:
Oil and gas properties, on the basis of full-cost accounting		(3,176,723)
Other property and equipment		(5,965)
Less accumulated depreciation, depletion, amortization and impairment		3,449,241
Net property and equipment		266,553
TOTAL		266,553
CURRENT LIABILITIES:
ASSET RETIREMENT OBLIGATIONS		(6,385)
COMMITMENTS AND CONTINGENCIES
STOCKHOLDERS' EQUITY (DEFICIT):
Retained deficit		272,938
Total stockholders' equity (deficit)		272,938
TOTAL		266,553
Predecessor
CURRENT ASSETS:
Cash and cash equivalents		274,530	76,540	$ 81,093	$ 11,557	$ 33,163
Accounts receivable:
Oil and gas sales		33,895		33,656
Joint interest billing		4,739		12,503
Other		26		17,506
Other current assets		8,425		1,044
Total current assets		321,615		145,802
PROPERTY AND EQUIPMENT:
Oil and gas properties, on the basis of full-cost accounting		3,795,943
Other property and equipment		12,175		14,798
Less accumulated depreciation, depletion, amortization and impairment		(3,449,241)		(3,157,332)
Net property and equipment		358,877		523,869
OTHER NONCURRENT ASSETS		3,701		9,496
TOTAL		684,193		679,167
CURRENT LIABILITIES:
Accounts payable		10,294		1,904
Accrued liabilities		65,240		91,712
Debt classified as current less unamortized debt issuance costs		249,384		1,890,944
Total current liabilities		324,918		1,984,560
ASSET RETIREMENT OBLIGATIONS		20,368		18,708	21,599	26,308
OTHER LONG-TERM LIABILITIES		617		1,965
LIABILITIES SUBJECT TO COMPROMISE (Note 2)		1,882,187
COMMITMENTS AND CONTINGENCIES
STOCKHOLDERS' EQUITY (DEFICIT):
Preferred stock
Common stock		104		110
Treasury stock		(3,134)
Treasury stock				3,081
Additional paid-in-capital		891,292		888,247
Retained deficit		(2,432,159)		(2,211,342)
Total stockholders' equity (deficit)		(1,543,897)	$ (1)	(1,326,066)	$ 465,862	$ 339,999
TOTAL		684,193		$ 679,167
Predecessor | Reorganization Adjustments
STOCKHOLDERS' EQUITY (DEFICIT):
Common stock		(104)
Treasury stock		(3,134)
Additional paid-in-capital		$ (891,292)