Intangible Assets (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011	Dec. 31, 2011
Intangible assets subject to amortization
Accumulated amortization	$ (5,376)		$ (5,376)		$ (4,924)
Intangible assets
Total intangible assets	2,450		2,450		2,936
Amortization expense for intangible assets	126	185	466	552
Customer lists
Intangible assets subject to amortization
Gross	4,298		4,298		4,315
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	946		946		946
Estimated Life			10 years
Design and technologies
Intangible assets subject to amortization
Gross	2,558		2,558		2,575
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	$ 24		$ 24		$ 24