Reconciliation of Beginning and Ending Balances of Gross Unrecognized Tax Benefits (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Reconciliation of Unrecognized Tax Benefits [Line Items]
Balance as of January 1,	$ 43,396	$ 40,929	$ 26,317
Additions based on tax positions related to the current year	817	4,041	4,320
Additions for tax positions of prior years	183	285	350
(Reductions) Additions for acquired uncertain tax benefits		(716)	10,268
Reductions for tax positions of prior years	(19,855)	(853)	(50)
Reductions for a lapse of the applicable statute of limitations	(569)	(290)	(276)
Balance as of December 31,	$ 23,972	$ 43,396	$ 40,929