Business Combinations (Summary of FDIC Indemnification Asset) (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
FDIC Indemnification Asset [Roll Forward]
Balance at beginning of period	$ (11,729)	$ 3,429	$ (6,100)	$ 11,846
Additions from acquisitions	0	0	0	0
Additions from reimbursable expenses	21	1,039	752	3,548
Accretion (amortization)	4	(718)	(189)	(3,184)
Changes in expected reimbursements from the FDIC for changes in expected credit losses	(4,537)	(5,236)	(10,284)	(13,546)
Payments received from the FDIC	(1,704)	(1,547)	(2,124)	(1,697)
Balance at end of period	$ (17,945)	$ (3,033)	$ (17,945)	$ (3,033)