Leasing Arrangements (Details) (USD $)	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Leasing Arrangements [Abstract]
Operating Leases, Future Minimum Payments Due, Current	$ 32,180,000
Operating Leases, Future Minimum Payments, Due in Two Years	28,788,000
Operating Leases, Future Minimum Payments, Due in Three Years	25,240,000
Operating Leases, Future Minimum Payments, Due in Four Years	17,284,000
Operating Leases, Future Minimum Payments, Due in Five Years	9,720,000
Operating Leases, Future Minimum Payments, Due Thereafter	16,134,000
Operating Leases, Future Minimum Payments Due	129,346,000
Operating Leases, Rent Expense, Net	$ 56,600,000	$ 56,700,000	$ 61,400,000