Goodwill and other intangible assets - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Finite-Lived Intangible Assets [Line Items]
In-process research and development impairment charge	$ 0	$ 41,000	$ 0
Amortization expense of intangible assets	98,766	63,491	$ 62,380
Trade names
Finite-Lived Intangible Assets [Line Items]
Indefinite lived intangible assets	236,100
In-process research and development
Finite-Lived Intangible Assets [Line Items]
In-process research and development impairment charge		41,000
Impairment of Intangible Assets, Indefinite-lived (Excluding Goodwill), Net Of Tax		$ 26,100
Trade name
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Net	$ 57,100
Useful life of Intangible assets, in years	25 years