Premises, Furniture, and Equipment (Detail) - Rental Expense - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Property, Plant and Equipment [Abstract]
Lease expense charged to operations	[1]	$ 5,706	$ 4,216	$ 3,123
Rental income from premises leased to others	[2]	606	541	531
Net operating lease expense		5,100	3,675	$ 2,592
Accretion of below market lease		$ 1,100	$ 453

[1] Includes amounts paid under short-term cancelable leases and included in net occupancy and equipment expense in the Consolidated Statements of Income. As of December 31, 2015 and 2014, lease expense is net of accretion related to the intangible liability of $1.1 million and $453,000, respectively.

[2] Included as a reduction to net occupancy and equipment expense in the Consolidated Statements of Income.