Subsidiary Guarantor Condensed Consolidating Balance Sheets (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Cash and cash equivalents	$ 45,923	$ 180,675
Accounts receivable, net	181,025	197,598
Fair value of derivatives	28,610	14,338
Prepaid expenses and other current assets	8,897	8,613
Total current assets	264,455	401,224
Properties and equipment, net	4,231,257	3,933,467
Assets held-for-sale, net	1,647	40,084
Intercompany Receivables	0	0
Investments in Affiliates, Subsidiaries, Associates, and Joint Ventures, Fair Value Disclosure	0	0
Other assets	24,798	45,116
Total Assets	4,522,157	4,419,891
Accounts payable	195,703	150,067
Production tax liability	36,650	37,654
Fair value of derivatives	110,683	79,302
Funds held for distribution	97,611	95,811
Accrued interest payable	13,760	11,815
Other accrued expenses	33,777	42,987
Total current liabilities	488,184	417,636
Intercompany Payable	0	0
Long-term debt	1,154,528	1,151,932
Deferred income taxes	187,183	191,992
Asset retirement obligations	73,905	71,006
Fair value of derivatives	26,426	22,343
Other liabilities	94,557	57,333
Total liabilities	2,024,783	1,912,242
Common shares - par value $0.01 per share, 150,000,000 authorized, 65,999,010 and 65,955,080 issued as of March 31, 2018 and December 31, 2017, respectively	660	659
Additional paid-in capital	2,504,663	2,503,294
Retained earnings (deficit)	(6,435)	6,704
Treasury Stock, Value	1,514	3,008
Total stockholders' equity	2,497,374	2,507,649
Total Liabilities and Stockholders' Equity	4,522,157	4,419,891
Corporate, Non-Segment [Member]
Cash and cash equivalents	45,923	180,675
Accounts receivable, net	143,250	160,490
Fair value of derivatives	28,610	14,338
Prepaid expenses and other current assets	7,116	8,284
Total current assets	224,899	363,787
Properties and equipment, net	2,139,471	1,891,314
Assets held-for-sale, net	1,647	40,084
Intercompany Receivables	294,476	250,279
Investments in Affiliates, Subsidiaries, Associates, and Joint Ventures, Fair Value Disclosure	1,605,330	1,617,537
Other assets	23,339	42,547
Total Assets	4,289,162	4,205,548
Accounts payable	113,529	85,000
Production tax liability	35,309	35,902
Fair value of derivatives	110,683	79,302
Funds held for distribution	80,203	83,898
Accrued interest payable	13,756	11,812
Other accrued expenses	33,136	42,543
Total current liabilities	386,616	338,457
Intercompany Payable	0	0
Long-term debt	1,154,528	1,151,932
Deferred income taxes	62,088	62,857
Asset retirement obligations	67,922	65,301
Fair value of derivatives	26,426	22,343
Other liabilities	94,208	57,009
Total liabilities	1,791,788	1,697,899
Common shares - par value $0.01 per share, 150,000,000 authorized, 65,999,010 and 65,955,080 issued as of March 31, 2018 and December 31, 2017, respectively	660	659
Additional paid-in capital	2,504,663	2,503,294
Retained earnings (deficit)	(6,435)	6,704
Treasury Stock, Value	1,514	3,008
Total stockholders' equity	2,497,374	2,507,649
Total Liabilities and Stockholders' Equity	4,289,162	4,205,548
Reportable Legal Entities [Member]
Cash and cash equivalents	0	0
Accounts receivable, net	37,775	37,108
Fair value of derivatives	0	0
Prepaid expenses and other current assets	1,781	329
Total current assets	39,556	37,437
Properties and equipment, net	2,091,786	2,042,153
Assets held-for-sale, net	0	0
Intercompany Receivables	0	0
Investments in Affiliates, Subsidiaries, Associates, and Joint Ventures, Fair Value Disclosure	0	0
Other assets	1,459	2,569
Total Assets	2,132,801	2,082,159
Accounts payable	82,174	65,067
Production tax liability	1,341	1,752
Fair value of derivatives	0	0
Funds held for distribution	17,408	11,913
Accrued interest payable	4	3
Other accrued expenses	641	444
Total current liabilities	101,568	79,179
Intercompany Payable	294,476	250,279
Long-term debt	0	0
Deferred income taxes	125,095	129,135
Asset retirement obligations	5,983	5,705
Fair value of derivatives	0	0
Other liabilities	349	324
Total liabilities	527,471	464,622
Common shares - par value $0.01 per share, 150,000,000 authorized, 65,999,010 and 65,955,080 issued as of March 31, 2018 and December 31, 2017, respectively	0	0
Additional paid-in capital	1,766,777	1,766,775
Retained earnings (deficit)	(161,447)	(149,238)
Treasury Stock, Value	0	0
Total stockholders' equity	1,605,330	1,617,537
Total Liabilities and Stockholders' Equity	2,132,801	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	0
Intercompany Receivables	(294,476)	(250,279)
Investments in Affiliates, Subsidiaries, Associates, and Joint Ventures, Fair Value Disclosure	(1,605,330)	(1,617,537)
Other assets	0	0
Total Assets	(1,899,806)	(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	(294,476)	(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	(294,476)	(250,279)
Common shares - par value $0.01 per share, 150,000,000 authorized, 65,999,010 and 65,955,080 issued as of March 31, 2018 and December 31, 2017, respectively	0	0
Additional paid-in capital	(1,766,777)	(1,766,775)
Retained earnings (deficit)	161,447	149,238
Treasury Stock, Value	0	0
Total stockholders' equity	(1,605,330)	(1,617,537)
Total Liabilities and Stockholders' Equity	$ (1,899,806)	$ (1,867,816)