Condensed Consolidating Financial Statements (Narrative) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011	Sep. 30, 2010	Dec. 31, 2010
Schedule of Equity Method Investments [Line Items]
Equity investments	$ 287,979		$ 287,979		$ 379,001
Income (Loss) from equity investments	10,666	6,675	22,749	12,054
OPCO [Member]
Schedule of Equity Method Investments [Line Items]
Equity investments	2,800		2,800
Income (Loss) from equity investments			(300)
Non Guarantor Unrestricted Equity Method Subsidiaries [Member]
Schedule of Equity Method Investments [Line Items]
Equity investments	285,200		285,200
Percentage of total assets			7.40%
Income (Loss) from equity investments			$ 23,000