Property & Equipment Depreciation Expense (Details) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Property And Equipment [Abstract]
Depreciation Expense	$ 23,100,000	$ 27,500,000	$ 29,500,000
Depreciation Expense Recorded in Cost of Sales	4,600,000	11,500,000	14,700,000
Asset Impairment Charges	$ 1,400,000	$ 500,000	$ 100,000