Leases (Narrative) (Details) (USD $)	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Leases
Lease Expiration Date	2031
Capital Leased Assets, Gross	$ 18,968,000
Capital Leases, Lessee Balance Sheet, Assets by Major Class, Accumulated Depreciation	5,583,000
Operating Leases, Rent Expense, Net	$ 42,413,000	$ 37,301,000	$ 35,401,000