Schedule II Valuation and Qualifying Accounts (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Allowance for excess and obsolete inventory [Member]
Movement in Valuation Allowances and Reserves
Valuation Allowances and Reserves, Beginning Balance	$ 417	$ 558	$ 1,221
Valuation Allowances and Reserves, Additions charged to costs and expenses	73	158	203
Valuation Allowances and Reserves, Deductions	(138)	(299)	(866)
Valuation Allowances and Reserves, Ending Balance	352	417	558
Allowance for Trade Receivables [Member]
Movement in Valuation Allowances and Reserves
Valuation Allowances and Reserves, Beginning Balance	1,382	855	1,045
Valuation Allowances and Reserves, Additions charged to costs and expenses	1,045	1,244	851
Valuation Allowances and Reserves, Deductions	(1,945)	(717)	(1,041)
Valuation Allowances and Reserves, Ending Balance	$ 482	$ 1,382	$ 855