Significant Accounting Policies - Additional Cash Flow Information (Detail) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015
Accounting Policies [Abstract]
Cash paid for interest	$ 5,770	$ 6,845
Cash paid for income taxes	25,979	22,300
Securities purchased not yet settled	306,564	50,567
Loans foreclosed and transferred to other real estate owned and foreclosed assets	422	161
Loans to facilitate the sale of other real estate owned	$ 0	$ 20