Commitments and Contingencies (Details) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Loss Contingency [Abstract]
Supplemental Unemployment Benefits, Severance Benefits	$ 7,100,000
Operating Leases, Rent Expense	21,600,000	20,900,000	18,400,000
Operating Leases, Future Minimum Payments Due [Abstract]
Operating Leases, Future Minimum Payments Due, Current	13,548,000
Operating Leases, Future Minimum Payments, Due in Two Years	9,544,000
Operating Leases, Future Minimum Payments, Due in Three Years	6,823,000
Operating Leases, Future Minimum Payments, Due in Four Years	4,806,000
Operating Leases, Future Minimum Payments, Due in Five Years	3,618,000
Operating Leases, Future Minimum Payments, Due Thereafter	12,830,000
Operating Leases, Future Minimum Payments Due	$ 51,169,000