Loans (Activity Related to Accretable Yield of Loans Acquired With Evidence of Credit Quality Deterioration Since Origination) (Detail) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Accretable Yield Movement Schedule [Roll Forward]
Accretable yield, beginning balance		$ 63,643	$ 97,281	$ 79,102	$ 115,909
Acquisitions		9,095	0	9,993	0
Accretable yield amortized to interest income		5,939	7,847	18,359	28,438
Accretable yield amortized to indemnification asset	[1]	3,280	8,784	10,945	25,593
Reclassification from non-accretable difference	[2]	2,298	2,584	5,154	29,092
Increases (decreases) in interest cash flows due to payments and changes in interest rates		(610)	4,675	262	(3,061)
Accretable yield, ending balance	[3]	65,207	$ 87,909	65,207	$ 87,909
Accretable yield, to be amortized to indemnification asset		$ 10,000		$ 10,000

[1] Represents the portion of the current period accreted yield, resulting from lower expected losses, applied to reduce the loss share indemnification asset.

[2] Reclassification is the result of subsequent increases in expected principal cash flows.

[3] As of September 30, 2015, the Company estimates that the remaining accretable yield balance to be amortized to the indemnification asset for the bank acquisitions is $10.0 million. The remainder of the accretable yield related to bank acquisitions is expected to be amortized to interest income.