Commitments and Contingencies (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Commitments and Contingencies Disclosure [Abstract]
Rent expense	$ 20,306	$ 20,275	$ 25,684
Operating Leases, Future Minimum Payments Due, Fiscal Year Maturity [Abstract]
2013	18,800
2014	15,442
2015	11,773
2016	9,854
2017	7,228
After 2017	$ 15,300