Members' Equity - AOCI (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Accumulated other comprehensive loss, beginning balance			$ (7,099)
Unrealized gain on interest rate swaps, net	$ (2,157)	$ 1,076	(6,945)	$ (5,181)
Reclassification of unrealized loss on interest rate swaps into income	1,057	3,213	7,222	9,720
Unrealized gain (loss) on available-for-sale securities	6	(60)	129	(81)
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net			7,222
Other Comprehensive Income (Loss), Unrealized Holding Gain (Loss) on Securities Arising During Period, Net of Tax			(72)
Accumulated other comprehensive loss, ending balance	(6,693)		(6,693)
Reclassification of other-than-temporary impairment of available-for-sale securities into operations	0	$ 0	(201)	$ 0
Unrealized Gain (Loss) on Derivaitve Instruments [Member]
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Accumulated other comprehensive loss, beginning balance			(6,976)
Unrealized gain on interest rate swaps, net			(6,945)
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net			7,222
Accumulated other comprehensive loss, ending balance	(6,699)		(6,699)
Unrealized Gain (Loss) on Available-For-Sale Securities [Member]
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Accumulated other comprehensive loss, beginning balance			(123)
Other Comprehensive Income (Loss), Unrealized Holding Gain (Loss) on Securities Arising During Period, Net of Tax			(72)
Accumulated other comprehensive loss, ending balance	$ 6		6
Reclassification of other-than-temporary impairment of available-for-sale securities into operations			$ 201