Debt Debt Outstanding (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012
Debt Instrument [Line Items]
Term Loans	$ 557,500	$ 563,625
Unamortized discount	(1,108)	(1,195)
Long-term Line of Credit	0	235,000
Senior Credit Facility	556,392	797,430
Non Recourse Debt Excluding Premium Discount	118,198	124,947
Non-Recourse Debt	116,839	123,482
Capital Lease Obligations	12,678	12,994
Other Long-term Debt	423	512
Long Term Debt Non Recourse Debt and Capital Lease Obligation Including Current Portion Net of Discount	1,539,436	1,488,173
Current portion of capital lease obligations, long-term debt and non-recourse debt (including VIEs of $5,450 and $5,200, respectively)	(59,627)	(53,882)
Capital Lease Obligations, Noncurrent	(11,678)	(11,926)
Non-Recourse Debt (including VIEs of $11,569 and $16,997 respectively)	(97,964)	(104,836)
Long-term Debt, Excluding Current Maturities	1,370,167	1,317,529
5.125% Senior Notes
Debt Instrument [Line Items]
Senior Notes	300,000	0
6.625% Senior Notes [Member]
Debt Instrument [Line Items]
Senior Notes	300,000	300,000
7.75% Senior Notes [Member]
Debt Instrument [Line Items]
Unamortized discount	(2,352)	(2,457)
Senior Notes	250,000	250,000
Swap on Notes	5,456	6,212
Senior Notes Net of Discount	253,104	253,755
Non Recourse Debt [Member]
Debt Instrument [Line Items]
Unamortized discount	$ (1,359)	$ (1,465)