Schedule of Amortization of Acquired Intangible Assets (Detail) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
		Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Finite-Lived Intangible Assets [Line Items]
Amortization of acquired intangible assets		$ 92,360	$ 92,672	$ 208,955	$ 187,978
Cost of sales
Finite-Lived Intangible Assets [Line Items]
Amortization of acquired intangible assets		889	711	1,779	1,422
Selling, general and administrative expenses
Finite-Lived Intangible Assets [Line Items]
Amortization of acquired intangible assets		986	949	1,983	1,899
Amortization of acquired intangible assets
Finite-Lived Intangible Assets [Line Items]
Amortization of acquired intangible assets	[1]	$ 90,485	$ 91,012	$ 205,193	$ 184,657

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