Consolidated Statements of Operations - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Income Statement [Abstract]
Revenues	$ 982,362	$ 948,447	$ 918,614
Costs and expenses:
Service costs (exclusive of depreciation and amortization)	401,751	381,014	365,436
Selling, general and administrative expenses	182,144	180,084	185,188
Management fee expense	19,000	17,650	16,600
Depreciation and amortization	144,220	153,478	156,397
Operating income	235,247	216,221	194,993
Interest expense, net	(94,668)	(100,436)	(96,203)
Gain on derivatives, net	9,173	23,226	22,782
Loss on early extinguishment of debt (Note 6)	(4,382)	(300)	(832)
Other expense, net	(1,377)	(1,262)	(1,793)
Net income	143,993	137,449	118,947
Dividend to preferred members (Note 7)	(18,000)	(18,000)	(18,000)
Net income applicable to member	$ 125,993	$ 119,449	$ 100,947