Goodwill and Intangible Assets (Intangible Assets) (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 211,199	$ 214,810
Accumulated Amortization	63,789	59,270
Total intangible Assets, Gross Carrying Amount	215,798	219,548
Net Carrying Amount	147,410	155,540
Indefinite-lived other intangible asset	4,599	4,738
Total intangible assets, Net Carrying Amount	152,009	160,278
Customer relationships
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	127,885	128,907
Accumulated Amortization	25,815	22,514
Net Carrying Amount	102,070	106,393
Technology
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	72,374	73,891
Accumulated Amortization	35,175	33,491
Net Carrying Amount	37,199	40,400
Trademarks and trade names
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	10,180	10,213
Accumulated Amortization	2,649	2,157
Net Carrying Amount	7,531	8,056
Covenants not to compete
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	760	1,799
Accumulated Amortization	150	1,108
Net Carrying Amount	$ 610	$ 691