Commitments and Contingencies (Future minimum lease payments) (Details) (USD $)	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Operating Leased Assets [Line Items]
Operating Leases, Future Minimum Payments Due, Current	$ 10,191,000
Operating Leases, Future Minimum Payments, Due in Two Years	7,536,000
Operating Leases, Future Minimum Payments, Due in Three Years	7,031,000
Operating Leases, Future Minimum Payments, Due in Four Years	5,141,000
Operating Leases, Future Minimum Payments, Due in Five Years	827,000
Operating Leases, Future Minimum Payments, Due Thereafter	2,955,000
Operating Leases, Future Minimum Payments Due	33,681,000
Operating Leases, Rent Expense, Net	$ 15,100,000	$ 16,300,000	$ 18,300,000