Segments (Reconciliation of reportable segment adjusted EBITDA) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Reconciliation from Segment Totals to Consolidated [Abstract]
Adjusted EBITDA	$ 58,649	$ 54,829
Less depreciation and amortization expense	(33,999)	(32,380)
Less share-based compensation expense	(1,259)	(1,730)
Less non-cash contribution expense	0	(800)
Less loss attributable to non-controlling interest	(200)	(177)
Plus net loss (income) attributable to equity investment	(4)	131
Less accretion expense	(127)	(188)
Operating income	23,060	19,685
Less Other expense, net	(16,904)	(17,284)
Income before income tax expense	$ 6,156	$ 2,401