Intangible Assets (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012	Dec. 31, 2012
Intangible assets subject to amortization
Accumulated amortization	$ (5,656)		$ (5,656)		$ (5,529)
Total intangible assets	2,228		2,228		2,431
Amortization expense for intangible assets	85	166	169	340
Customer lists
Intangible assets subject to amortization
Gross Amount	4,327		4,327		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		946
Estimated Life			10 years
Design and technologies
Intangible assets subject to amortization
Gross Amount	2,587		2,587		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		$ 24