Activity Related to Unrecognized Tax Benefits (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Income Tax Disclosure [Abstract]
Unrecognized tax benefit beginning Balance	$ 23,854	$ 23,131	$ 21,672
Increases related to prior year tax positions	6,636	47	543
Increases related to current year tax positions	2,584	676	916
Expiration of the statute of limitations for the assessment of taxes	0	0	0
Unrecognized tax benefit ending Balance	$ 33,074	$ 23,854	$ 23,131