Debt (Details1) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2010
Long-term debt
Total current maturities of long-term debt	$ 32,208	$ 24,524
Total long-term debt, less current maturities	238,885	276,825
Recourse [Member]
Long-term debt
Other notes payable and bonds	0	8
Total long-term debt	270,139	285,358
Total current maturities of long-term debt	32,051	21,683
Total long-term debt, less current maturities	238,088	263,675
Note payable, 4.80%, payable at maturity, due 2011 [ Member] | Recourse [Member]
Long-term debt
Total long-term debt	0	17,000
Note payable, 4.55%, payable at maturity, due 2012 [Member] | Recourse [Member]
Long-term debt
Total long-term debt	25,000	25,000
Note payable, 5.52 %, payable at maturity, due 2013 [Member] | Recourse [Member]
Long-term debt
Total long-term debt	25,000	25,000
Note payable, 6.10%, payable at maturity, due 2014 [Member] | Recourse [Member]
Long-term debt
Total long-term debt	25,000	25,000
Note payable, 6.12%, payable at maturity, due 2015 [Member] | Recourse [Member]
Long-term debt
Total long-term debt	61,500	61,500
Note payable, 6.78%, payable at maturity due 2018 [Member] | Recourse [Member]
Long-term debt
Total long-term debt	41,500	41,500
Note payable, variable rate (2.82% at December 31, 2010), payable $110 monthly plus interest, due 2012 [Member] | Recourse [Member]
Long-term debt
Total long-term debt	0	10,031
Note payable, variable rate (1.69% at December 31, 2011), payable in increasing amounts ($875 annually at December 31, 2011) plus interest, due 2023 [Member] | Recourse [Member]
Long-term debt
Total long-term debt	13,715	14,590
Note payable, variable rate (1.09% at December 31, 2011), payable $58 monthly plus interest, due 2016 [Member] | Recourse [Member]
Long-term debt
Total long-term debt	10,150	10,850
Note payable, 8.5%, payable $15 monthly, due 2016 [Member] | Recourse [Member]
Long-term debt
Total long-term debt	1,160	1,242
Variable rate (2.76% at December 31, 2011), due 2017 [Member] | Recourse [Member]
Long-term debt
Total long-term debt	8,881	9,000
Variable rate (2.19% at December 31, 2011), due 2019 [Member] | Recourse [Member]
Long-term debt
Total long-term debt	4,650	4,650
Variable rate (2.25% at December 31, 2011), due 2025 [Member] | Recourse [Member]
Long-term debt
Total long-term debt	3,100	3,100
Variable rate (1.87% at December 31, 2011), due 2036 [Member] | Recourse [Member]
Long-term debt
Total long-term debt	21,000	0
Debenture bonds, 4.00% to 6.5%, due 2011 through 2021 [Member] | Recourse [Member]
Long-term debt
Total long-term debt	$ 29,483	$ 36,887