Subsidiary Guarantors - Balance Sheets (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017	Mar. 31, 2017	Dec. 31, 2016
Current assets:
Cash and cash equivalents	$ 23,153	$ 28,441		$ 31,610
Accounts receivable, net	26,692	34,896
Accrued revenue	279,923	300,122
Derivative instruments	459,892	460,685
Other current assets	10,374	8,943
Total current assets	800,034	833,087
Unproved properties	2,265,727	2,266,673
Proved properties	11,471,428	11,096,462
Water handling and treatment systems	974,389	946,670
Gathering systems and facilities	2,132,803	2,050,490
Other property and equipment	59,499	57,429
Property and equipment, gross	16,903,846	16,417,724
Less accumulated depletion, depreciation, and amortization	(3,410,098)	(3,182,171)
Property and equipment, net	13,493,748	13,235,553
Derivative instruments	760,562	841,257
Investments in unconsolidated affiliates	321,468	303,302
Other assets, net	47,037	48,291
Total assets	15,422,849	15,261,490	$ 14,888,654
Liabilities and Stockholders' Equity
Accounts payable	73,221	62,982
Accrued liabilities	422,617	443,225
Revenue distributions payable	237,907	209,617
Derivative Liability, Current	41,907	28,476
Other current liabilities	14,201	17,796
Total current liabilities	789,853	762,096
Long-term debt	4,876,706	4,800,090
Deferred income tax liability	788,765	779,645
Derivative instruments		207
Other liabilities	46,427	43,316
Total liabilities	6,501,751	6,385,354
Common stock	3,165	3,164
Additional paid-in capital	6,588,082	6,570,952
Accumulated earnings	1,589,898	1,575,065
Total stockholders' equity	8,181,145	8,149,181
Noncontrolling interest in consolidated subsidiary	739,953	726,955
Total equity	8,921,098	8,876,136
Total liabilities and equity	15,422,849	15,261,490
Reportable legal entity | Parent
Current assets:
Cash and cash equivalents	14,439	20,078		17,568
Accounts receivable, net	25,447	33,726
Intercompany receivables	2,765	6,459
Accrued revenue	279,923	300,122
Derivative instruments	459,892	460,685
Other current assets	9,217	8,273
Total current assets	791,683	829,343
Unproved properties	2,265,727	2,266,673
Proved properties	11,902,297	11,460,615
Gathering systems and facilities	17,825	17,929
Other property and equipment	59,499	57,429
Property and equipment, gross	14,245,348	13,802,646
Less accumulated depletion, depreciation, and amortization	(3,008,346)	(2,812,851)
Property and equipment, net	11,237,002	10,989,795
Derivative instruments	760,562	841,257
Investment in subsidiaries	(629,293)	(573,926)
Contingent acquisition consideration asset	211,888	208,014
Other assets, net	33,245	35,371
Total assets	12,405,087	12,329,854
Liabilities and Stockholders' Equity
Accounts payable	65,845	54,340
Intercompany payable	111,001	110,182
Accrued liabilities	350,769	338,819
Revenue distributions payable	237,907	209,617
Derivative Liability, Current	41,907	28,476
Other current liabilities	13,973	17,587
Total current liabilities	821,402	759,021
Long-term debt	3,575,426	3,604,090
Deferred income tax liability	788,765	779,645
Derivative instruments		207
Other liabilities	42,990	42,906
Total liabilities	5,228,583	5,185,869
Common stock	3,165	3,164
Additional paid-in capital	5,583,441	5,565,756
Accumulated earnings	1,589,898	1,575,065
Total stockholders' equity	7,176,504	7,143,985
Total equity	7,176,504	7,143,985
Total liabilities and equity	12,405,087	12,329,854
Reportable legal entity | Non-Guarantor Subsidiaries
Current assets:
Cash and cash equivalents	8,714	8,363		$ 14,042
Accounts receivable, net	1,245	1,170
Intercompany receivables	111,001	110,182
Other current assets	1,157	670
Total current assets	122,117	120,385
Water handling and treatment systems	965,499	942,361
Gathering systems and facilities	2,114,978	2,032,561
Property and equipment, gross	3,080,477	2,974,922
Less accumulated depletion, depreciation, and amortization	(401,752)	(369,320)
Property and equipment, net	2,678,725	2,605,602
Investments in unconsolidated affiliates	321,468	303,302
Other assets, net	13,792	12,920
Total assets	3,136,102	3,042,209
Liabilities and Stockholders' Equity
Accounts payable	7,376	8,642
Intercompany payable	2,765	6,459
Accrued liabilities	70,369	106,006
Other current liabilities	228	209
Total current liabilities	80,738	121,316
Long-term debt	1,301,280	1,196,000
Contingent acquisition consideration liability	211,888	208,014
Other liabilities	3,437	410
Total liabilities	1,597,343	1,525,740
Partners' capital	1,538,759	1,516,469
Total stockholders' equity	1,538,759	1,516,469
Total equity	1,538,759	1,516,469
Total liabilities and equity	3,136,102	3,042,209
Eliminations
Current assets:
Intercompany receivables	(113,766)	(116,641)
Total current assets	(113,766)	(116,641)
Proved properties	(430,869)	(364,153)
Water handling and treatment systems	8,890	4,309
Property and equipment, gross	(421,979)	(359,844)
Property and equipment, net	(421,979)	(359,844)
Investment in subsidiaries	629,293	573,926
Contingent acquisition consideration asset	(211,888)	(208,014)
Total assets	(118,340)	(110,573)
Liabilities and Stockholders' Equity
Intercompany payable	(113,766)	(116,641)
Accrued liabilities	1,479	(1,600)
Total current liabilities	(112,287)	(118,241)
Contingent acquisition consideration liability	(211,888)	(208,014)
Total liabilities	(324,175)	(326,255)
Partners' capital	(1,538,759)	(1,516,469)
Additional paid-in capital	1,004,641	1,005,196
Total stockholders' equity	(534,118)	(511,273)
Noncontrolling interest in consolidated subsidiary	739,953	726,955
Total equity	205,835	215,682
Total liabilities and equity	$ (118,340)	$ (110,573)