Significant Accounting Policies - Additional Cash Flow Information (Detail) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014
Accounting Policies [Abstract]
Cash paid for interest	$ 6,845	$ 6,461
Cash paid for income taxes	22,300	27,188
Unsettled security transactions	50,567	0
Loans foreclosed and transferred to other real estate owned and foreclosed assets	161	1,622
Loans to facilitate the sale of other real estate owned	$ 20	$ 102