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 doubtful accounts receivable [Member]
Deducted from asset accounts:
Balance at Beginning of Period	$ 1,490	$ 1,452	$ 1,397
Charged to Costs and Expenses	560	285	423
Charged to Other Accounts-Describe	(305)	0	315
Deduction-Describe	342	247	683
Balance at End of Period	1,403	1,490	1,452
Inventory reserves and obsolescence [Member]
Deducted from asset accounts:
Balance at Beginning of Period	5,005	4,609	4,228
Charged to Costs and Expenses	2,836	878	3,309
Charged to Other Accounts-Describe	0	0	46
Deduction-Describe	3,024	482	2,974
Balance at End of Period	$ 4,817	$ 5,005	$ 4,609