Fair Value (Details 4) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Commodity Derivative Contracts (net)
Derivative assets and liabilities classified by the Partnership within Level 3 of the valuation hierarchy
Fair value at beginning of period	$ (751)	$ 12,477	$ (5,460)	$ 12,449
Total gain (loss) (realized and unrealized) included in earnings	(1,961)	16,896	(4,238)	20,220
Settlements	620	(2,995)	7,606	(6,291)
Fair value at end of period	(2,092)	26,378	(2,092)	26,378
The amount of total losses for the period included in earnings attributable to the change in unrealized gains or losses relating to contracts still held at end of period	(1,758)	14,755	(1,319)	17,854
Embedded Derivatives in Commodity Contracts (net)
Derivative assets and liabilities classified by the Partnership within Level 3 of the valuation hierarchy
Fair value at beginning of period	(28,486)	(24,881)	(35,032)	(33,957)
Total gain (loss) (realized and unrealized) included in earnings	(16,479)	20,459	(12,068)	26,991
Settlements	2,134	2,019	4,269	4,563
Fair value at end of period	(42,831)	(2,403)	(42,831)	(2,403)
The amount of total losses for the period included in earnings attributable to the change in unrealized gains or losses relating to contracts still held at end of period	$ (15,959)	$ 20,766	$ (12,204)	$ 27,229