Income Taxes - Roll Forward of Liability for Unrecognized Tax Benefits Exclusive of Accrued Interest (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Balance, beginning of period	$ 3,325	$ 3,110	$ 2,903
(Decrease) increase in previous year tax positions	(389)	0	57
Increase in current year tax positions	270	121	144
Decrease due to lapse of statute of limitations	(14)	0	0
Increase related to adjustment of previous estimates of activity	204	94	6
Balance, end of period	$ 3,396	$ 3,325	$ 3,110