Consolidated Statements Of Cash Flows (Unaudited) (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011
Cash flows from operating activities:
Net income (loss)	$ 91,890	$ (17,561)
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Depreciation, depletion and amortization	40,130	38,330
Accretion of asset retirement obligations	1,730	1,314
Recognition of unit-based awards	768	624
General and administrative expense contributed by affiliates	14,963	13,916
Unrealized (gains) losses on derivative contracts	(65,624)	3,192
Deferred income tax benefit	590	86
Other items	1,461	1,081
Changes in operating assets and liabilities:
Accounts receivable and other assets	(3,566)	(23,269)
Accounts payable and other liabilities	2,713	2,583
Net cash provided by operating activities	85,055	20,296
Cash flows from investing activities:
Additions to oil and gas properties	(63,087)	(29,898)
Proceeds from the sale of oil and gas leases	240	1,327
Acquisitions	(225,118)
Net cash used in investing activities	(287,965)	(28,571)
Cash flows from financing activities:
Proceeds from unit offering, net of offering costs	162,195	41,963
Distributions to the Fund		(42,000)
Contributions from the General Partner		715
Management incentive fee to the General Partner	(1,730)
Distributions to unitholders	(45,351)	(16,416)
Contributions from the Predecessor		(18,816)
Proceeds from bank borrowings	96,500	41,000
Deferred financing costs	(3,608)	(214)
Net cash provided by financing activities	208,006	6,232
Increase (decrease) in cash	5,096	(2,043)
Cash at beginning of period	17,433	2,195
Cash at end of period	$ 22,529	$ 152