Stockholders' Equity - Schedule of Accumulated Other Comprehensive Income Loss (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated other comprehensive income, net of tax, Beginning balance			$ 1,580,664
Other comprehensive income (loss), net of tax	$ 20,463	$ (6,037)	37,471	$ (54,167)
Accumulated other comprehensive income, net of tax, Ending balance	1,630,128		1,630,128
Foreign Currency Translation [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated other comprehensive income, net of tax, Beginning balance			(128,671)
Other comprehensive income (loss) before reclassifications, net of tax			37,479
Less: Amounts reclassified from accumulated other comprehensive income (loss)			0
Other comprehensive income (loss), net of tax			37,479
Accumulated other comprehensive income, net of tax, Ending balance	(91,192)		(91,192)
Unrealized Gains (Losses) on Available-for-Sale Securities [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated other comprehensive income, net of tax, Beginning balance			(23)
Other comprehensive income (loss) before reclassifications, net of tax			(8)
Less: Amounts reclassified from accumulated other comprehensive income (loss)			0
Other comprehensive income (loss), net of tax			(8)
Accumulated other comprehensive income, net of tax, Ending balance	(31)		(31)
Accumulated Other Comprehensive Income [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated other comprehensive income, net of tax, Beginning balance			(128,694)
Other comprehensive income (loss) before reclassifications, net of tax			37,471
Less: Amounts reclassified from accumulated other comprehensive income (loss)			0
Other comprehensive income (loss), net of tax			37,471
Accumulated other comprehensive income, net of tax, Ending balance	$ (91,223)		$ (91,223)