Goodwill and Intangible Assets (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2010
Summary of company's intangible assets
Cost	$ 9,390	$ 9,390
Accumulated Amortization	(6,630)	(5,162)
Net Carrying Amount	2,760	4,228
Technology [Member]
Summary of company's intangible assets
Cost	4,010	4,010
Accumulated Amortization	(3,202)	(2,505)
Net Carrying Amount	808	1,505
Customer relationships [Member]
Summary of company's intangible assets
Cost	3,530	3,530
Accumulated Amortization	(1,999)	(1,584)
Net Carrying Amount	1,531	1,946
Non-competition agreements [Member]
Summary of company's intangible assets
Cost	1,260	1,260
Accumulated Amortization	(962)	(710)
Net Carrying Amount	298	550
Trade names [Member]
Summary of company's intangible assets
Cost	590	590
Accumulated Amortization	(467)	(363)
Net Carrying Amount	$ 123	$ 227