GUARANTOR FINANCIAL STATEMENTS - Condensed Consolidating Statement of Cash Flows (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Cash flows from operating activities:
Net loss	$ (116,406)	$ (89,635)	$ (195,761)	$ (188,784)	$ (318,656)	$ (291,965)	$ (152,906)	$ (327,388)	$ (590,586)	$ (1,090,915)	$ (189,543)
Adjustments to reconcile net loss to net cash provided by operating activities:
Depreciation, depletion and amortization									220,079	281,688	340,006
Write-down of oil and gas properties	73,094	$ 36,484	$ 118,649	129,204	351,062	$ 295,679	$ 224,294	491,412	357,431	1,362,447	351,192
Accretion expense									40,229	25,988	28,411
Deferred income tax provision (benefit)									13,080	(272,311)	(102,177)
Settlement of asset retirement obligations									(20,514)	(72,382)	(56,409)
Non-cash stock compensation expense									8,443	12,324	11,325
Excess tax benefits									0	(1,586)	0
Non-cash derivative expense									1,471	16,440	(18,028)
Non-cash interest expense									18,404	17,788	16,661
Non-cash reorganization items									8,332	0	0
Other non-cash expense									6,248	0	0
Change in current income taxes									20,088	(37,377)	158
Non-cash loss from investment in subsidiaries									0	0	0
Change in intercompany receivables/payables									0	0	0
(Increase) decrease in accounts receivable									(1,412)	43,724	51,611
(Increase) decrease in other current assets									(3,493)	1,767	(6,244)
(Increase) decrease in inventory									0	1,304	0
Increase (decrease) in accounts payable									1,026	(14,582)	(3,419)
Increase (decrease) in other current liabilities									9,897	(25,936)	(19,152)
Other									(10,135)	(907)	(3,251)
Net cash provided by operating activities									78,588	247,474	401,141
Cash flows from investing activities:
Investment in oil and gas properties									(237,952)	(522,047)	(927,247)
Proceeds from sale of oil and gas properties, net of expenses									0	22,839	242,914
Investment in fixed and other assets									(1,266)	(1,549)	(10,182)
Change in restricted funds									1,046	179,467	(178,072)
Investment in subsidiaries									0	0	0
Net cash used in investing activities									(238,172)	(321,290)	(872,587)
Cash flows from financing activities:
Proceeds from bank borrowings									477,000	5,000	0
Repayments of bank borrowings									(135,500)	(5,000)	0
Proceeds from issuance of common stock									0	0	225,999
Deferred financing costs									(900)	(68)	(3,371)
Proceeds from building loan									0	11,770	0
Repayments of building loan									(423)	0	0
Excess tax benefits									0	1,586	0
Equity proceeds from parent									0	0	0
Net payments for share-based compensation									(762)	(3,127)	(7,182)
Net cash provided by financing activities									339,415	10,161	215,446
Effect of exchange rate changes on cash									(9)	(74)	(736)
Net change in cash and cash equivalents									179,822	(63,729)	(256,736)
Cash and cash equivalents, beginning of year				10,759				74,488	10,759	74,488	331,224
Cash and cash equivalents, end of year	190,581				10,759				190,581	10,759	74,488
Eliminations
Cash flows from operating activities:
Net loss									299,064	279,442	(133,368)
Adjustments to reconcile net loss to net cash provided by operating activities:
Depreciation, depletion and amortization									0	0	0
Write-down of oil and gas properties									0	0	0
Accretion expense									0	0	0
Deferred income tax provision (benefit)									0	0	0
Settlement of asset retirement obligations									0	0	0
Non-cash stock compensation expense									0	0	0
Excess tax benefits										0
Non-cash derivative expense									0	0	0
Non-cash interest expense									0	0	0
Non-cash reorganization items									0
Other non-cash expense									0
Change in current income taxes									0	0	0
Non-cash loss from investment in subsidiaries									(299,064)	(279,442)	133,368
Change in intercompany receivables/payables									0	0	0
(Increase) decrease in accounts receivable									0	0	0
(Increase) decrease in other current assets									0	0	0
(Increase) decrease in inventory										0	0
Increase (decrease) in accounts payable									0	0	0
Increase (decrease) in other current liabilities									0	0	0
Other									0	0	0
Net cash provided by operating activities									0	0	0
Cash flows from investing activities:
Investment in oil and gas properties									0	0	0
Proceeds from sale of oil and gas properties, net of expenses										0	0
Investment in fixed and other assets									0	0	0
Change in restricted funds									0	0	0
Investment in subsidiaries									(715)	9,714	31,696
Net cash used in investing activities									(715)	9,714	31,696
Cash flows from financing activities:
Proceeds from bank borrowings									0	0
Repayments of bank borrowings									0	0
Proceeds from issuance of common stock											0
Deferred financing costs									0	0	0
Proceeds from building loan										0
Repayments of building loan									0
Excess tax benefits										0
Equity proceeds from parent									715	(9,714)	(31,696)
Net payments for share-based compensation									0	0	0
Net cash provided by financing activities									715	(9,714)	(31,696)
Effect of exchange rate changes on cash									0	0	0
Net change in cash and cash equivalents									0	0	0
Cash and cash equivalents, beginning of year				0				0	0	0	0
Cash and cash equivalents, end of year	0				0				0	0	0
Parent
Cash flows from operating activities:
Net loss									(590,586)	(1,090,915)	(189,543)
Adjustments to reconcile net loss to net cash provided by operating activities:
Depreciation, depletion and amortization									67,059	123,724	138,313
Write-down of oil and gas properties									26,706	785,463	351,192
Accretion expense									232	365	230
Deferred income tax provision (benefit)									0	(114,418)	(177,197)
Settlement of asset retirement obligations									(85)	(15)	(201)
Non-cash stock compensation expense									8,443	12,324	11,325
Excess tax benefits										(1,586)
Non-cash derivative expense									0	0	0
Non-cash interest expense									18,404	17,788	16,661
Non-cash reorganization items									8,332
Other non-cash expense									168
Change in current income taxes									20,088	(37,377)	158
Non-cash loss from investment in subsidiaries									292,618	231,783	(133,336)
Change in intercompany receivables/payables									43,330	9,744	114,056
(Increase) decrease in accounts receivable									(7,490)	34,609	1,131
(Increase) decrease in other current assets									(3,526)	1,799	(6,238)
(Increase) decrease in inventory										(1,394)	2,415
Increase (decrease) in accounts payable									4,313	(7,471)	(662)
Increase (decrease) in other current liabilities									10,321	(25,989)	(16,946)
Other									(9,178)	256	(1,755)
Net cash provided by operating activities									(110,851)	(61,310)	109,603
Cash flows from investing activities:
Investment in oil and gas properties									(86,442)	(188,154)	(338,731)
Proceeds from sale of oil and gas properties, net of expenses										0	28,103
Investment in fixed and other assets									(1,266)	(1,549)	(10,182)
Change in restricted funds									0	177,647	(177,647)
Investment in subsidiaries									0	0	0
Net cash used in investing activities									(87,708)	(12,056)	(498,457)
Cash flows from financing activities:
Proceeds from bank borrowings									477,000	5,000
Repayments of bank borrowings									(135,500)	(5,000)
Proceeds from issuance of common stock											225,999
Deferred financing costs									(900)	(68)	(3,371)
Proceeds from building loan										11,770
Repayments of building loan									(423)
Excess tax benefits										1,586
Equity proceeds from parent									0	0	0
Net payments for share-based compensation									(762)	(3,127)	(7,182)
Net cash provided by financing activities									339,415	10,161	215,446
Effect of exchange rate changes on cash									0	0	0
Net change in cash and cash equivalents									140,856	(63,205)	(173,408)
Cash and cash equivalents, beginning of year				9,681				72,886	9,681	72,886	246,294
Cash and cash equivalents, end of year	150,537				9,681				150,537	9,681	72,886
Guarantor Subsidiary
Cash flows from operating activities:
Net loss									(286,172)	(184,124)	133,304
Adjustments to reconcile net loss to net cash provided by operating activities:
Depreciation, depletion and amortization									153,020	157,964	201,693
Write-down of oil and gas properties									330,373	529,354	0
Accretion expense									39,997	25,623	28,181
Deferred income tax provision (benefit)									13,080	(157,893)	75,020
Settlement of asset retirement obligations									(19,530)	(72,367)	(56,208)
Non-cash stock compensation expense									0	0	0
Excess tax benefits										0
Non-cash derivative expense									1,471	16,440	(18,028)
Non-cash interest expense									0	0	0
Non-cash reorganization items									0
Other non-cash expense									0
Change in current income taxes									0	0	0
Non-cash loss from investment in subsidiaries									0	0	0
Change in intercompany receivables/payables									(42,449)	(19,486)	(145,250)
(Increase) decrease in accounts receivable									6,078	9,084	50,514
(Increase) decrease in other current assets									0	0	0
(Increase) decrease in inventory										2,698	(2,415)
Increase (decrease) in accounts payable									(3,287)	(7,111)	(2,757)
Increase (decrease) in other current liabilities									(424)	53	(2,206)
Other									(957)	(1,163)	(1,496)
Net cash provided by operating activities									191,200	299,072	260,352
Cash flows from investing activities:
Investment in oil and gas properties									(151,158)	(323,359)	(558,003)
Proceeds from sale of oil and gas properties, net of expenses										22,839	214,811
Investment in fixed and other assets									0	0	0
Change in restricted funds									0	0	0
Investment in subsidiaries									0	0	0
Net cash used in investing activities									(151,158)	(300,520)	(343,192)
Cash flows from financing activities:
Proceeds from bank borrowings									0	0
Repayments of bank borrowings									0	0
Proceeds from issuance of common stock											0
Deferred financing costs									0	0	0
Proceeds from building loan										0
Repayments of building loan									0
Excess tax benefits										0
Equity proceeds from parent									0	0	0
Net payments for share-based compensation									0	0	0
Net cash provided by financing activities									0	0	0
Effect of exchange rate changes on cash									0	0	0
Net change in cash and cash equivalents									40,042	(1,448)	(82,840)
Cash and cash equivalents, beginning of year				2				1,450	2	1,450	84,290
Cash and cash equivalents, end of year	40,044				2				40,044	2	1,450
Non- Guarantor Subsidiaries
Cash flows from operating activities:
Net loss									(12,892)	(95,318)	64
Adjustments to reconcile net loss to net cash provided by operating activities:
Depreciation, depletion and amortization									0	0	0
Write-down of oil and gas properties									352	47,630	0
Accretion expense									0	0	0
Deferred income tax provision (benefit)									0	0	0
Settlement of asset retirement obligations									(899)	0	0
Non-cash stock compensation expense									0	0	0
Excess tax benefits										0
Non-cash derivative expense									0	0	0
Non-cash interest expense									0	0	0
Non-cash reorganization items									0
Other non-cash expense									6,080
Change in current income taxes									0	0	0
Non-cash loss from investment in subsidiaries									6,446	47,659	(32)
Change in intercompany receivables/payables									(881)	9,742	31,194
(Increase) decrease in accounts receivable									0	31	(34)
(Increase) decrease in other current assets									33	(32)	(6)
(Increase) decrease in inventory										0	0
Increase (decrease) in accounts payable									0	0	0
Increase (decrease) in other current liabilities									0	0	0
Other									0	0	0
Net cash provided by operating activities									(1,761)	9,712	31,186
Cash flows from investing activities:
Investment in oil and gas properties									(352)	(10,534)	(30,513)
Proceeds from sale of oil and gas properties, net of expenses										0	0
Investment in fixed and other assets									0	0	0
Change in restricted funds									1,046	1,820	(425)
Investment in subsidiaries									715	(9,714)	(31,696)
Net cash used in investing activities									1,409	(18,428)	(62,634)
Cash flows from financing activities:
Proceeds from bank borrowings									0	0
Repayments of bank borrowings									0	0
Proceeds from issuance of common stock											0
Deferred financing costs									0	0	0
Proceeds from building loan										0
Repayments of building loan									0
Excess tax benefits										0
Equity proceeds from parent									(715)	9,714	31,696
Net payments for share-based compensation									0	0	0
Net cash provided by financing activities									(715)	9,714	31,696
Effect of exchange rate changes on cash									(9)	(74)	(736)
Net change in cash and cash equivalents									(1,076)	924	(488)
Cash and cash equivalents, beginning of year				$ 1,076				$ 152	1,076	152	640
Cash and cash equivalents, end of year	$ 0				$ 1,076				$ 0	$ 1,076	$ 152