Members' Equity Members' Equity (AOCI) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	$ (7,099)	$ (11,933)
Deferred losses on interest rate swaps	(6,851)	(7,999)	$ 772
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net	8,548	12,896
Unrealized gain (loss) on available-for-sale securities	(102)	(63)
Reclassification of other-than-temporary impairment of available-for-sale securities into operations	201	0	0
Ending balance	(5,303)	(7,099)	(11,933)
Unrealized Gain (Loss) on Derivative Instruments [Member]
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	(6,976)	(11,873)
Deferred losses on interest rate swaps	(6,851)	(7,999)
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net	8,548	12,896
Ending balance	(5,279)	(6,976)	(11,873)
Unrealized Gain (Loss) on Securities [Member]
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	(123)	(60)
Unrealized gain (loss) on available-for-sale securities	(102)	(63)
Reclassification of other-than-temporary impairment of available-for-sale securities into operations	201
Ending balance	$ (24)	$ (123)	$ (60)