Condensed Consolidating Financial Information (Cash Flows) (Details) (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011
Cash flows from operating activities
Net cash provided by operating activities	$ 108,773	$ 97,568
Cash flows from investing activities
Capital expenditures	(70,403)	(30,874)
Investment in subsidiaries	0	0
Other investing activities	2,334	223
Net cash used in investing activities	(68,069)	(30,651)
Cash flows from financing activities
Borrowings under bank credit facility	843,000	401,620
Payments under bank credit facility	(1,042,950)	(442,520)
Payments on long-term debt		(340)
Debt financing costs, net	(10,246)	(828)
Proceeds from issuance of non-recourse debt	351,935	5,250
Other financing activities	(744)	58
Net cash provided by (used in) financing activities	140,995	(36,760)
Change in cash and cash equivalents	181,699	30,157
Cash and cash equivalents, beginning of period	178,756	145,623
Cash and cash equivalents, end of period	360,455	175,780
Parent
Cash flows from operating activities
Net cash provided by operating activities	(133,564)	64,350
Cash flows from investing activities
Capital expenditures	(22,421)	0
Investment in subsidiaries	(1)	787
Other investing activities	0	55
Net cash used in investing activities	(22,422)	842
Cash flows from financing activities
Borrowings under bank credit facility	488,500	35,920
Payments under bank credit facility	(672,450)	(35,920)
Payments on long-term debt		0
Debt financing costs, net	(10,246)	(149)
Proceeds from issuance of non-recourse debt	350,000	0
Other financing activities	117	239
Net cash provided by (used in) financing activities	155,921	90
Change in cash and cash equivalents	(65)	65,282
Cash and cash equivalents, beginning of period	364	11,232
Cash and cash equivalents, end of period	299	76,514
Guarantor Subsidiaries
Cash flows from operating activities
Net cash provided by operating activities	5,981	7,102
Cash flows from investing activities
Capital expenditures	(17,537)	(20,563)
Investment in subsidiaries	0	0
Other investing activities	126	0
Net cash used in investing activities	(17,411)	(20,563)
Cash flows from financing activities
Borrowings under bank credit facility	0	0
Payments under bank credit facility	0	0
Payments on long-term debt		(340)
Debt financing costs, net	0	0
Proceeds from issuance of non-recourse debt	0	0
Other financing activities	(360)	0
Net cash provided by (used in) financing activities	(360)	(340)
Change in cash and cash equivalents	(11,790)	(13,801)
Cash and cash equivalents, beginning of period	128,185	88,281
Cash and cash equivalents, end of period	116,395	74,480
Non-Guarantor Subsidiaries (100% Owned)
Cash flows from operating activities
Net cash provided by operating activities	205,894	464
Cash flows from investing activities
Capital expenditures	(108)	(217)
Investment in subsidiaries	0	0
Other investing activities	5	0
Net cash used in investing activities	(103)	(217)
Cash flows from financing activities
Borrowings under bank credit facility	0	0
Payments under bank credit facility	0	0
Payments on long-term debt		0
Debt financing costs, net	0	0
Proceeds from issuance of non-recourse debt	0	0
Other financing activities	0	0
Net cash provided by (used in) financing activities	0	0
Change in cash and cash equivalents	205,791	247
Cash and cash equivalents, beginning of period	3,944	3,679
Cash and cash equivalents, end of period	209,735	3,926
Non-Guarantor Subsidiaries (Not 100% Owned)
Cash flows from operating activities
Net cash provided by operating activities	30,462	25,652
Cash flows from investing activities
Capital expenditures	(30,337)	(10,094)
Investment in subsidiaries	1	(787)
Other investing activities	2,203	168
Net cash used in investing activities	(28,133)	(10,713)
Cash flows from financing activities
Borrowings under bank credit facility	354,500	365,700
Payments under bank credit facility	(370,500)	(406,600)
Payments on long-term debt		0
Debt financing costs, net	0	(679)
Proceeds from issuance of non-recourse debt	1,935	5,250
Other financing activities	(501)	(181)
Net cash provided by (used in) financing activities	(14,566)	(36,510)
Change in cash and cash equivalents	(12,237)	(21,571)
Cash and cash equivalents, beginning of period	46,263	42,431
Cash and cash equivalents, end of period	34,026	20,860
Eliminations
Cash flows from operating activities
Net cash provided by operating activities	0	0
Cash flows from investing activities
Capital expenditures	0	0
Investment in subsidiaries	0	0
Other investing activities	0	0
Net cash used in investing activities	0	0
Cash flows from financing activities
Borrowings under bank credit facility	0	0
Payments under bank credit facility	0	0
Payments on long-term debt		0
Debt financing costs, net	0	0
Proceeds from issuance of non-recourse debt	0	0
Other financing activities	0	0
Net cash provided by (used in) financing activities	0	0
Change in cash and cash equivalents	0	0
Cash and cash equivalents, beginning of period	0	0
Cash and cash equivalents, end of period	$ 0	$ 0