Guarantor Financial Statements - Condensed Consolidating Statement of Cash Flows (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Cash flows from operating activities:
Net loss	$ (188,784)	$ (327,388)
Adjustments to reconcile net loss to net cash provided by operating activities:
Depreciation, depletion and amortization	61,558	86,422
Write-down of oil and gas properties	129,204	491,412
Accretion expense	9,983	6,409
Deferred income tax provision (benefit)	2,877	(179,906)
Settlement of asset retirement obligations	(4,667)	(17,145)
Non-cash stock compensation expense	2,312	2,640
Non-cash derivative expense	192	1,511
Non-cash interest expense	4,635	4,318
Other non-cash expense	6,081	0
Change in current income taxes	(1,074)	7,188
Non-cash loss from investment in subsidiaries		0
Change in intercompany receivables/payables		0
(Increase) decrease in accounts receivable	5,845	8,206
(Increase) decrease in other current assets	(185)	1,883
(Increase) decrease in inventory		0
Decrease in accounts payable	(2,138)	(8,657)
Increase in other current liabilities	3,898	6,889
Other	(298)	(260)
Net cash provided by operating activities	29,439	83,522
Cash flows from investing activities:
Investment in oil and gas properties	(129,859)	(169,895)
Investment in fixed and other assets	(496)	(662)
Change in restricted funds	1,045	177,642
Investment in subsidiaries		0
Net cash (used in) provided by investing activities	(129,310)	7,085
Cash flows from financing activities:
Proceeds from bank borrowings	477,000	5,000
Repayments of bank borrowings	(20,000)	(5,000)
Repayments of building loan	(95)	0
Equity proceeds from parent		0
Net payments for share-based compensation	(650)	(2,991)
Net cash provided by (used in) financing activities	456,255	(2,991)
Effect of exchange rate changes on cash	(9)	24
Net change in cash and cash equivalents	356,375	87,640
Cash and cash equivalents, beginning of period	10,759	74,488
Cash and cash equivalents, end of period	367,134	162,128
Parent
Cash flows from operating activities:
Net loss	(188,784)	(327,388)
Adjustments to reconcile net loss to net cash provided by operating activities:
Depreciation, depletion and amortization	8,594	42,112
Write-down of oil and gas properties	9,324	491,412
Accretion expense	58	91
Deferred income tax provision (benefit)	0	(196,234)
Settlement of asset retirement obligations	0	(1)
Non-cash stock compensation expense	2,312	2,640
Non-cash derivative expense		0
Non-cash interest expense	4,635	4,318
Change in current income taxes	(1,074)	7,188
Non-cash loss from investment in subsidiaries	131,282	(29,027)
Change in intercompany receivables/payables	(1,657)	(33,748)
(Increase) decrease in accounts receivable	(36,703)	3,606
(Increase) decrease in other current assets	(218)	1,881
(Increase) decrease in inventory		(2,415)
Decrease in accounts payable	45	(1,007)
Increase in other current liabilities	3,813	6,347
Other	(39)	(249)
Net cash provided by operating activities	(68,412)	(30,474)
Cash flows from investing activities:
Investment in oil and gas properties	(29,895)	(84,470)
Investment in fixed and other assets	(496)	(662)
Change in restricted funds	0	177,647
Investment in subsidiaries		0
Net cash (used in) provided by investing activities	(30,391)	92,515
Cash flows from financing activities:
Proceeds from bank borrowings	477,000	5,000
Repayments of bank borrowings	(20,000)	(5,000)
Repayments of building loan	(95)
Equity proceeds from parent		0
Net payments for share-based compensation	(650)	(2,991)
Net cash provided by (used in) financing activities	456,255	(2,991)
Effect of exchange rate changes on cash		0
Net change in cash and cash equivalents	357,452	59,050
Cash and cash equivalents, beginning of period	9,681	72,886
Cash and cash equivalents, end of period	367,133	131,936
Guarantor Subsidiaries
Cash flows from operating activities:
Net loss	(124,839)	29,027
Adjustments to reconcile net loss to net cash provided by operating activities:
Depreciation, depletion and amortization	52,964	44,310
Write-down of oil and gas properties	119,531	0
Accretion expense	9,925	6,318
Deferred income tax provision (benefit)	2,877	16,328
Settlement of asset retirement obligations	(3,768)	(17,144)
Non-cash stock compensation expense		0
Non-cash derivative expense	192	1,511
Non-cash interest expense		0
Change in current income taxes		0
Non-cash loss from investment in subsidiaries		0
Change in intercompany receivables/payables	1,657	25,548
(Increase) decrease in accounts receivable	43,432	4,600
(Increase) decrease in other current assets		0
(Increase) decrease in inventory		2,415
Decrease in accounts payable	(2,183)	(7,650)
Increase in other current liabilities	85	542
Other	(259)	(11)
Net cash provided by operating activities	99,614	105,794
Cash flows from investing activities:
Investment in oil and gas properties	(99,615)	(77,229)
Investment in fixed and other assets		0
Change in restricted funds		0
Investment in subsidiaries		0
Net cash (used in) provided by investing activities	(99,615)	(77,229)
Cash flows from financing activities:
Proceeds from bank borrowings		0
Repayments of bank borrowings		0
Equity proceeds from parent		0
Net payments for share-based compensation		0
Net cash provided by (used in) financing activities		0
Effect of exchange rate changes on cash		0
Net change in cash and cash equivalents	(1)	28,565
Cash and cash equivalents, beginning of period	2	1,450
Cash and cash equivalents, end of period	1	30,015
Non- Guarantor Subsidiaries
Cash flows from operating activities:
Net loss	(12,886)	0
Adjustments to reconcile net loss to net cash provided by operating activities:
Depreciation, depletion and amortization	0	0
Write-down of oil and gas properties	349	0
Accretion expense		0
Deferred income tax provision (benefit)	0	0
Settlement of asset retirement obligations	(899)	0
Non-cash stock compensation expense		0
Non-cash derivative expense		0
Non-cash interest expense		0
Other non-cash expense	6,081
Change in current income taxes		0
Non-cash loss from investment in subsidiaries	6,443	0
Change in intercompany receivables/payables	0	8,200
(Increase) decrease in accounts receivable	(884)	0
(Increase) decrease in other current assets	33	2
(Increase) decrease in inventory		0
Decrease in accounts payable		0
Increase in other current liabilities		0
Other		0
Net cash provided by operating activities	(1,763)	8,202
Cash flows from investing activities:
Investment in oil and gas properties	(349)	(8,196)
Investment in fixed and other assets		0
Change in restricted funds	1,045	(5)
Investment in subsidiaries	718	(8,168)
Net cash (used in) provided by investing activities	1,414	(16,369)
Cash flows from financing activities:
Proceeds from bank borrowings		0
Repayments of bank borrowings		0
Equity proceeds from parent	(718)	8,168
Net payments for share-based compensation		0
Net cash provided by (used in) financing activities	(718)	8,168
Effect of exchange rate changes on cash	(9)	24
Net change in cash and cash equivalents	(1,076)	25
Cash and cash equivalents, beginning of period	1,076	152
Cash and cash equivalents, end of period	0	177
Eliminations
Cash flows from operating activities:
Net loss	137,725	(29,027)
Adjustments to reconcile net loss to net cash provided by operating activities:
Depreciation, depletion and amortization	0	0
Write-down of oil and gas properties		0
Accretion expense		0
Deferred income tax provision (benefit)	0	0
Settlement of asset retirement obligations		0
Non-cash stock compensation expense		0
Non-cash derivative expense		0
Non-cash interest expense		0
Change in current income taxes		0
Non-cash loss from investment in subsidiaries	(137,725)	29,027
Change in intercompany receivables/payables		0
(Increase) decrease in accounts receivable		0
(Increase) decrease in other current assets		0
(Increase) decrease in inventory		0
Decrease in accounts payable		0
Increase in other current liabilities		0
Other		0
Net cash provided by operating activities	0	0
Cash flows from investing activities:
Investment in oil and gas properties		0
Investment in fixed and other assets		0
Change in restricted funds		0
Investment in subsidiaries	(718)	8,168
Net cash (used in) provided by investing activities	(718)	8,168
Cash flows from financing activities:
Proceeds from bank borrowings		0
Repayments of bank borrowings		0
Equity proceeds from parent	718	(8,168)
Net payments for share-based compensation		0
Net cash provided by (used in) financing activities	718	(8,168)
Effect of exchange rate changes on cash		0
Net change in cash and cash equivalents	0	0
Cash and cash equivalents, beginning of period	0	0
Cash and cash equivalents, end of period	$ 0	$ 0