Goodwill and Intangible Assets (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2012	Dec. 31, 2011
Summary of company's intangible assets
Cost	$ 9,390	$ 9,390
Accumulated Amortization	(6,985)	(6,630)
Net Carrying Amount	2,405	2,760
Technology [Member]
Summary of company's intangible assets
Cost	4,010	4,010
Accumulated Amortization	(3,377)	(3,202)
Net Carrying Amount	633	808
Customer relationships [Member]
Summary of company's intangible assets
Cost	3,530	3,530
Accumulated Amortization	(2,090)	(1,999)
Net Carrying Amount	1,440	1,531
Non-competition agreements [Member]
Summary of company's intangible assets
Cost	1,260	1,260
Accumulated Amortization	(1,025)	(962)
Net Carrying Amount	235	298
Tradenames [Member]
Summary of company's intangible assets
Cost	590	590
Accumulated Amortization	(493)	(467)
Net Carrying Amount	$ 97	$ 123