Goodwill and Other Intangible Assets (Details 2) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Dec. 31, 2015
Intangible Assets, by category
Gross Carrying Amount	$ 203,614		$ 202,824
Accumulated Amortization	153,041		149,766
Amortization expense for intangible assets	2,105	$ 2,137
Estimated amortization expense for next 5 years
2015	8,000
2016	5,500
2017	5,250
2018	4,750
2019	4,500
Customer related
Intangible Assets, by category
Gross Carrying Amount	153,667		153,287
Accumulated Amortization	113,175		111,227
Non-compete agreements
Intangible Assets, by category
Gross Carrying Amount	1,098		1,092
Accumulated Amortization	1,098		1,092
Patents
Intangible Assets, by category
Gross Carrying Amount	5,876		5,882
Accumulated Amortization	5,530		5,495
Technology related
Intangible Assets, by category
Gross Carrying Amount	25,895		25,559
Accumulated Amortization	24,060		23,089
Trade names
Intangible Assets, by category
Gross Carrying Amount	8,310		8,303
Accumulated Amortization	4,303		4,194
Other
Intangible Assets, by category
Gross Carrying Amount	8,768		8,701
Accumulated Amortization	$ 4,875		$ 4,669