Covered Loans - Summary of FDIC Loss Sharing Asset (Detail) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015
Receivables [Abstract]
Beginning balance	$ 9,030	$ 20,603
Adjustments not reflected in income:
Cash received from the FDIC	(10,000)	(2,231)
Other	512	612
Adjustments reflected in income:
(Amortization) accretion	(816)	(3,830)
Higher (lower) loan loss expectations	(13)	109
Impairment/(recovery) of value and net (gain)/loss on sales of other real estate	1,062	1,212
Gain as a result of the early termination agreement with the FDIC, effective June 22, 2016	$ 225
Ending balance		$ 16,475