Goodwill and Other Intangible Assets (Details 2) (USD $) In Thousands, unless otherwise specified	3 Months Ended			9 Months Ended
	Sep. 30, 2014		Sep. 30, 2013	Sep. 30, 2014		Sep. 30, 2013	Dec. 31, 2013
Intangible Assets, by category
Gross Carrying Amount	$ 210,521			$ 210,521			$ 196,695
Accumulated Amortization	148,253			148,253			143,434
Amortization expense for intangible assets	2,398		3,629	7,544		11,481
Estimated amortization expense for next 5 years
2014	10,000	[1]		10,000	[1]
2015	8,750	[1]		8,750	[1]
2016	8,250	[1]		8,250	[1]
2017	5,250	[1]		5,250	[1]
2018	5,000	[1]		5,000	[1]
Customer related
Intangible Assets, by category
Gross Carrying Amount	161,109			161,109			150,307
Accumulated Amortization	113,147			113,147			110,889
Non-compete agreements
Intangible Assets, by category
Gross Carrying Amount	1,114			1,114			1,126
Accumulated Amortization	1,038			1,038			1,024
Patents
Intangible Assets, by category
Gross Carrying Amount	6,169			6,169			6,211
Accumulated Amortization	5,412			5,412			5,273
Technology related
Intangible Assets, by category
Gross Carrying Amount	26,811			26,811			27,185
Accumulated Amortization	20,749			20,749			18,931
Trade names
Intangible Assets, by category
Gross Carrying Amount	7,751			7,751			4,113
Accumulated Amortization	3,544			3,544			2,969
Other
Intangible Assets, by category
Gross Carrying Amount	7,567			7,567			7,753
Accumulated Amortization	$ 4,363			$ 4,363			$ 4,348

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