Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	4 Months Ended	5 Months Ended	9 Months Ended
	Apr. 22, 2016	Sep. 30, 2016	Sep. 30, 2017
Predecessor [Member]
Cash Flows from Operating Activities:
Net Income (Loss)	$ 851,611
Adjustments to reconcile net income to net cash provided by operating activities -
Depreciation, depletion, and amortization	20,439
Write-down of oil and gas properties	77,732
Accretion of asset retirement obligation	1,610
Stock-based compensation expenses	886
Loss (gain) on derivatives	0
Cash settlements on derivatives	0
Settlements of asset retirement obligations	(848)
Debt issuance cost write-down	0
Reorganization items (non-cash)	(977,696)
Other Noncash Income (Expense)	229
(Increase) decrease in accounts receivable and other current assets	(5,474)
Increase (decrease) in accounts payable and accrued liabilities	(9,647)
Increase (decrease) in accrued interest	(308)
Net Cash Provided by (Used in) Operating Activities	(41,466)
Cash Flows from Investing Activities:
Additions to property and equipment	(24,530)
Proceeds from the sale of property and equipment	(48,661)
Net Cash Provided by (Used in) Investing Activities	24,131
Cash Flows from Financing Activities:
Proceeds from bank borrowings	328,000
Payments of bank borrowings	(324,900)
Net proceeds from issuances of common stock	0
Purchase of treasury shares	(4)
Payments of debt issuance costs	(6,482)
Net Cash Provided by (Used in) Financing Activities	(3,386)
Net increase (decrease) in Cash and Cash Equivalents	(20,721)
Cash and Cash Equivalents at Beginning of Period	29,460	$ 8,739
Cash and Cash Equivalents at End of Period	8,739
Supplemental Disclosures of Cash Flows Information:
Cash paid during period for interest, net of amounts capitalized	10,367
Cash paid for reorganization items	15,643
Changes in capital accounts payable and capital accruals	1,843
Successor [Member]
Cash Flows from Operating Activities:
Net Income (Loss)		(149,207)	$ 46,834
Adjustments to reconcile net income to net cash provided by operating activities -
Depreciation, depletion, and amortization		26,621	32,375
Write-down of oil and gas properties		133,496	0
Accretion of asset retirement obligation		1,931	1,722
Stock-based compensation expenses		3,132	4,538
Loss (gain) on derivatives		7,308	(14,465)
Cash settlements on derivatives		(1,100)	(2,503)
Settlements of asset retirement obligations		(1,919)	(2,245)
Debt issuance cost write-down		0	2,401
Reorganization items (non-cash)		0	0
Other Noncash Income (Expense)		1,721	760
(Increase) decrease in accounts receivable and other current assets		14,669	(3,884)
Increase (decrease) in accounts payable and accrued liabilities		(8,283)	1,605
Increase (decrease) in accrued interest		1,041	(86)
Net Cash Provided by (Used in) Operating Activities		29,410	67,052
Cash Flows from Investing Activities:
Additions to property and equipment		(36,794)	(141,636)
Proceeds from the sale of property and equipment		(594)	(653)
Net Cash Provided by (Used in) Investing Activities		(36,200)	(140,983)
Cash Flows from Financing Activities:
Proceeds from bank borrowings		49,000	349,000
Payments of bank borrowings		(48,000)	(297,000)
Net proceeds from issuances of common stock		0	39,180
Purchase of treasury shares		0	(618)
Payments of debt issuance costs		(502)	(4,073)
Net Cash Provided by (Used in) Financing Activities		498	86,489
Net increase (decrease) in Cash and Cash Equivalents		(6,292)	12,558
Cash and Cash Equivalents at Beginning of Period		8,739	303
Cash and Cash Equivalents at End of Period	$ 8,739	2,447	12,861
Supplemental Disclosures of Cash Flows Information:
Cash paid during period for interest, net of amounts capitalized		8,021	11,390
Cash paid for reorganization items		12,017	0
Changes in capital accounts payable and capital accruals		$ (17,554)	$ 9,375