Goodwill and Intangible Assets (Details 2) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Finite-Lived Intangible Assets [Line Items]
Total		$ 90,181	$ 91,983	$ 299,136	$ 279,961
Cost of sales
Finite-Lived Intangible Assets [Line Items]
Total		890	871	2,668	2,293
Selling, general and administrative expenses
Finite-Lived Intangible Assets [Line Items]
Total		986	950	2,969	2,849
Amortization of acquired intangible assets
Finite-Lived Intangible Assets [Line Items]
Total	[1]	$ 88,305	$ 90,162	$ 293,499	$ 274,819

[1] Reflects amortization expense for the intangible assets acquired through business combinations.