Goodwill and Other Intangible Assets (Goodwill) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Goodwill and Intangible Assets Disclosure [Abstract]
Payments to acquire business		$ 6,100
Goodwill [Roll Forward]
Goodwill beginning balance	$ 260,651	256,232
Goodwill resulting from business acquisitions	136,687	5,369
Reduction in goodwill resulting from a business acquisition purchase price allocation adjustment	0	(525)
Foreign currency translation	326	(425)
Goodwill ending balance	397,664	260,651
Accumulated goodwill impairment loss	$ 106,991	$ 106,991