Goodwill and Other Intangible Assets (Details 2) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014	Dec. 31, 2014
Intangible Assets, by category
Gross Carrying Amount		$ 205,270		$ 205,270		$ 206,429
Accumulated Amortization		148,988		148,988		147,905
Amortization expense for intangible assets		2,286	$ 2,398	6,602	$ 7,544
Estimated amortization expense for next 5 years
2015	[1]	9,000		9,000
2016	[1]	8,750		8,750
2017	[1]	6,000		6,000
2018	[1]	5,750		5,750
2019	[1]	5,500		5,500
Customer related
Intangible Assets, by category
Gross Carrying Amount		155,416		155,416		157,530
Accumulated Amortization		111,256		111,256		112,211
Non-compete agreements
Intangible Assets, by category
Gross Carrying Amount		1,097		1,097		1,107
Accumulated Amortization		1,047		1,047		1,039
Patents
Intangible Assets, by category
Gross Carrying Amount		5,912		5,912		6,079
Accumulated Amortization		5,474		5,474		5,399
Technology related
Intangible Assets, by category
Gross Carrying Amount		25,743		25,743		26,548
Accumulated Amortization		22,589		22,589		21,233
Trade names
Intangible Assets, by category
Gross Carrying Amount		8,308		8,308		7,745
Accumulated Amortization		4,077		4,077		3,733
Other
Intangible Assets, by category
Gross Carrying Amount		8,794		8,794		7,420
Accumulated Amortization		$ 4,545		$ 4,545		$ 4,290

[1] These estimated amortization expense amounts do not reflect the potential effect of future foreign currency exchange fluctuations.