Commitments and Contingencies (Details) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Lease Commitments
Rental expense under operating leases	$ 4,000,000	$ 4,300,000	$ 4,600,000
Future minimum lease commitments on non-cancelable operating leases
2014	2,762,000
2015	1,458,000
2016	312,000
2017	42,000
Total	4,574,000
Purchase Commitments
Non-cancelable contracts and purchase orders for inventory	$ 24,500,000