Goodwill and Other Intangible Assets - Other Intangible Assets, Changes in Net Carrying Amount (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Gross Amount
Other intangible assets, beginning	$ 420,546	$ 138,831
Intangible assets acquired, purchase accounting adjustment	(461)
Intangible assets acquired during the period		284,000
Impairment	(3,657)
Currency translation effect on foreign balances	7,418	(2,285)
Other intangible assets, ending	423,846	420,546
Accumulated Amortization
Other intangible assets, beginning	(49,130)	(33,728)
Amortization expense	(25,855)	(16,549)
Impairment	1,987
Currency translation effect on foreign balances	(3,636)	1,147
Other intangible assets, ending	$ (76,634)	$ (49,130)