Debt (Details) (USD $) In Thousands	Sep. 30, 2011	Dec. 31, 2010	Sep. 30, 2010
Long-term debt
Total current maturities of long-term debt	$ 45,171	$ 24,524	$ 23,953
Total long-term debt, less current maturities	235,729	276,825	264,349
Nonrecourse [Member]
Long-term debt
Total current maturities of long-term debt	2,806	2,841	3,081
Total long-term debt, less current maturities	6,971	13,150	13,853
Recourse [Member]
Long-term debt
Total current maturities of long-term debt	42,365	21,683	20,872
Total long-term debt, less current maturities	$ 228,758	$ 263,675	$ 250,496