Goodwill and Intangible Assets (Intangible Assets) (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 216,015	$ 214,810
Accumulated Amortization	63,883	59,270
Total intangible Assets, Gross Carrying Amount	220,881	219,548
Net Carrying Amount	152,132	155,540
Indefinite-lived other intangible asset	4,866	4,738
Total intangible assets, Net Carrying Amount	156,998	160,278
Customer relationships
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	129,330	128,907
Accumulated Amortization	24,675	22,514
Net Carrying Amount	104,655	106,393
Technology
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	74,671	73,891
Accumulated Amortization	35,645	33,491
Net Carrying Amount	39,026	40,400
Trademarks and patents
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	10,214	10,213
Accumulated Amortization	2,413	2,157
Net Carrying Amount	7,801	8,056
Covenants not to compete
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	1,800	1,799
Accumulated Amortization	1,150	1,108
Net Carrying Amount	$ 650	$ 691