Income Taxes - Reconciliation of Unrecognized Tax Benefits (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Income Tax Disclosure [Abstract]
Balance at beginning of year	$ 46,004	$ 43,796
Additions based on tax positions related to the current year	3,897	6,008
Reductions for tax positions of prior years	(3,310)	(3,800)
Settlements	0	0
Balance at end of year	$ 46,591	$ 46,004