Commitments, Contingencies, and Guarantees (Details 2) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Rental expense
Minimum Rentals	$ 20,429,000	$ 20,427,000	$ 20,187,000
Sublease Rental Income	(5,540,000)	(5,463,000)	(5,387,000)
Total	14,889,000	14,964,000	14,800,000
Future minimum payments for capital leases
2013	665,000
2014	665,000
2015	665,000
2016	665,000
2017	665,000
Thereafter	23,259,000
Total Future Minimum Lease Payments	26,584,000
Amounts Representing Interest	(17,714,000)
Present Value of Net Future Minimum Lease Payments	8,870,000
Future minimum payments for operating leases
2013	13,904,000
2014	12,368,000
2015	10,727,000
2016	10,002,000
2017	8,139,000
Thereafter	131,388,000
Total Future Minimum Lease Payments	186,528,000
Minimum future rental income receivable under subleases from non-cancelable operating leases	$ 17,100,000