Commitments and Contingencies (Details) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Lease Commitments
Rental expense under operating leases	$ 4,300,000	$ 4,600,000	$ 5,200,000
Future minimum lease commitments on non-cancelable operating leases
2013	3,057,000
2014	1,681,000
2015	1,181,000
2016	224,000
Total	6,143,000
Purchase Commitments
Non-cancelable contracts and purchase orders for inventory	$ 14,900,000