Goodwill and Intangible Assets - Finite Lived Intangible Assets Amortization Expense (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Goodwill And Intangible Assets Disclosure [Abstract]
Intangible assets – finite life, net at beginning of period			$ 49,956	$ 60,728
Amortization expense	$ (2,400)	$ (2,900)	(4,988)	(5,772)
Divestitures			(2,372)
Foreign currency adjustments			(152)	493
Intangible assets – finite life, net at end of period	$ 42,444	$ 55,449	$ 42,444	$ 55,449