Commitments and Contingencies (Details) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Operating Leased Assets [Line Items]
Operating Leases, Rent Expense	$ 5,800,000	$ 6,100,000	$ 5,300,000
Operating Leases, Future Minimum Payments Due, Current	5,329,000
Operating Leases, Future Minimum Payments, Due in Two Years	4,943,000
Operating Leases, Future Minimum Payments, Due in Three Years	4,671,000
Operating Leases, Future Minimum Payments, Due in Four Years	4,566,000
Operating Leases, Future Minimum Payments, Due in Five Years	4,553,000
Operating Leases, Future Minimum Payments, Due Thereafter	264,796,000
Operating Leases, Future Minimum Payments Due	288,858,000
Construction Commitments	$ 14,300,000