Consolidated Statements Of Cash Flows (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Cash flows from operating activities:
Net income (loss)	$ 61,628	$ 79,751	$ 88,295
Adjustments to reconcile net income (loss) to net cash provided by (used in) operating activities:
Depreciation, depletion and amortization	115,184	105,796	94,993
Accretion of asset retirement obligations	7,456	5,648	4,593
Amortization of deferred financing costs	2,424	2,898	2,101
Recognition of unit-based awards	6,880	3,252	1,351
General and administrative expense contributed by affiliates		38,076	34,721
Loss (gain) on derivative contracts, net	4,130	(42,850)	(18,434)
Cash received (paid) on settlement of derivative contracts	20,161	27,863	(76,565)
Deferred income tax (benefit) expense	(304)	372	849
Other items	2,935	2,075	357
Changes in operating assets and liabilities:
Accounts receivable and other assets	(21,762)	(8,531)	(29,386)
Accounts payable and other liabilities	3,413	12,800	9,682
Net cash provided by operating activities	202,145	227,150	112,557
Cash flows from investing activities:
Additions to oil and natural gas properties	(88,247)	(127,352)	(70,426)
Acquisitions, net of cash acquired	(128,234)	(468,009)	(3,044)
Proceeds from the sale of oil and natural gas properties		3,082	1,327
Proceeds from sale of available-for-sale securities	8,535
Purchases of available-for-sale securities	(10,249)
Net cash used in investing activities	(218,195)	(592,279)	(72,143)
Cash flows from financing activities:
Proceeds from unit offering, net of offering costs	87	376,938	41,963
Proceeds from senior note offering, net of underwriter discount		295,860
Distributions to the Fund			(42,000)
Proceeds from issuance of units to the general partner		115	715
Management incentive fee to the general partner	(3,357)	(7,692)
Distributions to unitholders	(141,582)	(96,472)	(46,026)
Contributions from (distributions to) the Predecessor		(34,973)	(25,507)
Proceeds from bank borrowings	180,000	476,500	275,000
Repayments on bank borrowings	(35,000)	(506,500)
Repayment of debt assumed from the Fund		(115,000)	(227,000)
Units withheld for employee payroll tax obligation	(583)	(322)
Deferred financing costs	(1,991)	(8,922)	(2,321)
Net cash provided by (used in) financing activities	(2,426)	379,532	(25,176)
Increase (decrease) in cash	(18,476)	14,403	15,238
Cash and cash equivalents at beginning of period	31,836	17,433	2,195
Cash and cash equivalents at ending of period	$ 13,360	$ 31,836	$ 17,433