Summary of Significant Accounting Policies (Details 2) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Summary of Significant Accounting Policies
Long-lived assets reclassified to held for sale	$ 0	$ 0
Net carrying value of intangible assets with definite lives
Gross Carrying Amount	13,362,000	13,150,000
Accumulated Amortization	(7,325,000)	(6,515,000)
Net	6,037,000	6,635,000
Amortization expense	704,000	742,000	749,000
Amortization expenses included in cost of sales	202,000	201,000	201,000
Expected annual amortization expense
2013	666,000
2014	635,000
2015	604,000
2016	573,000
2017	542,000
Customer relationship Canadian Government
Net carrying value of intangible assets with definite lives
Gross Carrying Amount	2,533,000	2,478,000
Accumulated Amortization	(640,000)	(544,000)
Net	1,893,000	1,934,000
Estimated Useful Life	30 years	30 years
Customer relationships other
Net carrying value of intangible assets with definite lives
Gross Carrying Amount	7,219,000	7,062,000
Accumulated Amortization	(4,603,000)	(4,091,000)
Net	2,616,000	2,971,000
Estimated Useful Life	20 years	20 years
Technology-based intangibles
Net carrying value of intangible assets with definite lives
Gross Carrying Amount	3,610,000	3,610,000
Accumulated Amortization	(2,082,000)	(1,880,000)
Net	$ 1,528,000	$ 1,730,000
Estimated Useful Life	15 years	15 years