Intangible Assets (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012	Dec. 31, 2012
Intangible assets subject to amortization
Accumulated amortization	$ (5,534)		$ (5,529)
Total intangible assets	2,278		2,431
Amortization expense for intangible assets	84	174
Customer lists
Intangible assets subject to amortization
Gross Amount	4,291		4,364
Customer lists | Minimum
Intangible assets subject to amortization
Estimated Life	8 years
Customer lists | Maximum
Intangible assets subject to amortization
Estimated Life	10 years
Trade name
Intangible assets subject to amortization
Gross Amount	946		946
Estimated Life	10 years
Design and technologies
Intangible assets subject to amortization
Gross Amount	2,551		2,626
Design and technologies | Minimum
Intangible assets subject to amortization
Estimated Life	8 years
Design and technologies | Maximum
Intangible assets subject to amortization
Estimated Life	10 years
Patents
Intangible assets subject to amortization
Gross Amount	$ 24		$ 24