Business Combinations (Summary of FDIC Indemnification Asset) (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
FDIC Indemnification Asset [Roll Forward]
Balance at beginning of period	$ 10,224	$ 60,298	$ 11,846	$ 85,672
Additions from acquisitions	0	0	0	0
Additions from reimbursable expenses	934	2,067	2,509	3,349
Amortization	(1,206)	(1,456)	(2,466)	(3,059)
Changes in expected reimbursements from the FDIC for changes in expected credit losses	(4,317)	(13,645)	(8,310)	(29,029)
Payments received from the FDIC	(2,206)	(1,149)	(150)	(10,818)
Balance at end of period	$ 3,429	$ 46,115	$ 3,429	$ 46,115