Loans (Activity Related to Accretable Yield of Loans Acquired With Evidence of Credit Quality Deterioration Since Origination) (Detail) (USD $)	3 Months Ended
	Mar. 31, 2015		Mar. 31, 2014
Schedule Of Accretable Yield Activity Related to Loans Acquired With Evidence Of Credit Quality Deterioration Since Origination Table [Line Items]
Certain Loans Acquired In Transfer Not Accounted fo as Debt Securities, Accretable Yield, To Be Amortized To Indem Asset	$ 15,800,000
Bank acquisitions
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Accretable Yield Movement Schedule [Roll Forward]
Accretable yield, beginning balance	77,485,000		107,655,000
Acquisitions	898,000		0
Accretable yield amortized to interest income	(5,504,000)		(7,770,000)
Accretable yield amortized to indemnification asset	(3,576,000)	[1]	(5,648,000)	[1]
Reclassification from non-accretable difference	1,103,000	[2]	8,580,000	[2]
(Decreases) increases in interest cash flows due to payments and changes in interest rates	(1,224,000)		(5,143,000)
Accretable yield, ending balance	69,182,000	[3]	97,674,000	[3]
Life insurance premium finance loans acquisition
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Accretable Yield Movement Schedule [Roll Forward]
Accretable yield, beginning balance	1,617,000		8,254,000
Acquisitions	0		0
Accretable yield amortized to interest income	(601,000)		(1,771,000)
Accretable yield amortized to indemnification asset	0	[1]	0	[1]
Reclassification from non-accretable difference	0	[2]	0	[2]
(Decreases) increases in interest cash flows due to payments and changes in interest rates	0		78,000
Accretable yield, ending balance	$ 1,016,000	[3]	$ 6,561,000	[3]

[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 March 31, 2015, the Company estimates that the remaining accretable yield balance to be amortized to the indemnification asset for the bank acquisitions is $15.8 million. The remainder of the accretable yield related to bank acquisitions is expected to be amortized to interest income.