Immaterial Correction of Prior Period Financial Statements (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Total revenues	$ 468,643	$ 444,947	$ 1,369,069	$ 1,265,308
Purchased gas, NGLs and crude oil	368,349	345,202	1,068,465	975,507
Total operating costs and expenses	531,476	444,048	1,411,894	1,223,955
Operating income	(62,833)	899	(42,825)	41,353
Scenario, Actual [Member]
Total revenues		444,947		1,265,308
Purchased gas, NGLs and crude oil		345,202		975,507
Total operating costs and expenses		444,048		1,223,955
Operating income		899		41,353
Classification of New Opportunity Processing [Member] | Scenario, Previously Reported [Member]
Total revenues		406,968		1,129,871
Purchased gas, NGLs and crude oil		307,223		840,070
Total operating costs and expenses		406,069		1,088,518
Operating income		899		41,353
Classification of New Opportunity Processing [Member] | Scenario, Adjustment [Member]
Purchased gas, NGLs and crude oil		$ 38,000		$ 135,400