Subsidiary Guarantor Condensed Consolidating Balance Sheets (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017	Jun. 30, 2017
Cash and cash equivalents	$ 1,425	$ 180,675	$ 202,291
Accounts receivable, net	195,317	197,598
Fair value of derivatives	14,817	14,338
Prepaid expenses and other current assets	6,744	8,613
Total current assets	218,303	401,224
Properties and equipment, net	4,192,608	3,933,467
Assets held-for-sale, net	0	40,084
Intercompany Receivables	0	0
Investments in Affiliates, Subsidiaries, Associates, and Joint Ventures, Fair Value Disclosure	0	0
Other assets	31,243	45,116
Total Assets	4,442,154	4,419,891
Accounts payable	215,150	150,067
Production tax liability	56,766	37,654
Fair value of derivatives	186,605	79,302
Funds held for distribution	102,354	95,811
Accrued interest payable	12,561	11,815
Other accrued expenses	35,888	42,987
Total current liabilities	609,324	417,636
Intercompany Payable	0	0
Long-term debt	1,179,117	1,151,932
Deferred income taxes	141,811	191,992
Asset retirement obligations	73,549	71,006
Fair value of derivatives	36,430	22,343
Other liabilities	61,617	57,333
Total liabilities	2,101,848	1,912,242
Common shares - par value $0.01 per share, 150,000,000 authorized, 66,133,025 and 65,955,080 issued as of June 30, 2018 and December 31, 2017, respectively	661	659
Additional paid-in capital	2,509,693	2,503,294
Retained earnings (deficit)	(166,692)	6,704
Treasury Stock, Value	3,356	3,008
Total stockholders' equity	2,340,306	2,507,649
Total Liabilities and Stockholders' Equity	4,442,154	4,419,891
Corporate, Non-Segment [Member]
Cash and cash equivalents	1,425	180,675
Accounts receivable, net	149,120	160,490
Fair value of derivatives	14,817	14,338
Prepaid expenses and other current assets	5,379	8,284
Total current assets	170,741	363,787
Properties and equipment, net	2,191,985	1,891,314
Assets held-for-sale, net		40,084
Intercompany Receivables	352,436	250,279
Investments in Affiliates, Subsidiaries, Associates, and Joint Ventures, Fair Value Disclosure	1,493,829	1,617,537
Other assets	27,069	42,547
Total Assets	4,236,060	4,205,548
Accounts payable	135,677	85,000
Production tax liability	52,768	35,902
Fair value of derivatives	186,605	79,302
Funds held for distribution	80,439	83,898
Accrued interest payable	12,556	11,812
Other accrued expenses	35,143	42,543
Total current liabilities	503,188	338,457
Intercompany Payable	0	0
Long-term debt	1,179,117	1,151,932
Deferred income taxes	48,740	62,857
Asset retirement obligations	67,142	65,301
Fair value of derivatives	36,430	22,343
Other liabilities	61,137	57,009
Total liabilities	1,895,754	1,697,899
Common shares - par value $0.01 per share, 150,000,000 authorized, 66,133,025 and 65,955,080 issued as of June 30, 2018 and December 31, 2017, respectively	661	659
Additional paid-in capital	2,509,693	2,503,294
Retained earnings (deficit)	(166,692)	6,704
Treasury Stock, Value	3,356	3,008
Total stockholders' equity	2,340,306	2,507,649
Total Liabilities and Stockholders' Equity	4,236,060	4,205,548
Reportable Legal Entities [Member]
Cash and cash equivalents	0	0
Accounts receivable, net	46,197	37,108
Fair value of derivatives	0	0
Prepaid expenses and other current assets	1,365	329
Total current assets	47,562	37,437
Properties and equipment, net	2,000,623	2,042,153
Assets held-for-sale, net		0
Intercompany Receivables	0	0
Investments in Affiliates, Subsidiaries, Associates, and Joint Ventures, Fair Value Disclosure	0	0
Other assets	4,174	2,569
Total Assets	2,052,359	2,082,159
Accounts payable	79,473	65,067
Production tax liability	3,998	1,752
Fair value of derivatives	0	0
Funds held for distribution	21,915	11,913
Accrued interest payable	5	3
Other accrued expenses	745	444
Total current liabilities	106,136	79,179
Intercompany Payable	352,436	250,279
Long-term debt	0	0
Deferred income taxes	93,071	129,135
Asset retirement obligations	6,407	5,705
Fair value of derivatives	0	0
Other liabilities	480	324
Total liabilities	558,530	464,622
Common shares - par value $0.01 per share, 150,000,000 authorized, 66,133,025 and 65,955,080 issued as of June 30, 2018 and December 31, 2017, respectively	0	0
Additional paid-in capital	1,766,775	1,766,775
Retained earnings (deficit)	(272,946)	(149,238)
Treasury Stock, Value	0	0
Total stockholders' equity	1,493,829	1,617,537
Total Liabilities and Stockholders' Equity	2,052,359	2,082,159
Consolidation, Eliminations [Member]
Cash and cash equivalents	0	0
Accounts receivable, net	0	0
Fair value of derivatives	0	0
Prepaid expenses and other current assets	0	0
Total current assets	0	0
Properties and equipment, net	0	0
Assets held-for-sale, net		0
Intercompany Receivables	(352,436)	(250,279)
Investments in Affiliates, Subsidiaries, Associates, and Joint Ventures, Fair Value Disclosure	(1,493,829)	(1,617,537)
Other assets	0	0
Total Assets	(1,846,265)	(1,867,816)
Accounts payable	0	0
Production tax liability	0	0
Fair value of derivatives	0	0
Funds held for distribution	0	0
Accrued interest payable	0	0
Other accrued expenses	0	0
Total current liabilities	0	0
Intercompany Payable	(352,436)	(250,279)
Long-term debt	0	0
Deferred income taxes	0	0
Asset retirement obligations	0	0
Fair value of derivatives	0	0
Other liabilities	0	0
Total liabilities	(352,436)	(250,279)
Common shares - par value $0.01 per share, 150,000,000 authorized, 66,133,025 and 65,955,080 issued as of June 30, 2018 and December 31, 2017, respectively	0	0
Additional paid-in capital	(1,766,775)	(1,766,775)
Retained earnings (deficit)	272,946	149,238
Treasury Stock, Value	0	0
Total stockholders' equity	(1,493,829)	(1,617,537)
Total Liabilities and Stockholders' Equity	$ (1,846,265)	$ (1,867,816)