Covered Assets (Carrying Amount Of Covered Assets) (Detail) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2012		Mar. 31, 2012	Dec. 31, 2011		Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2010
Total covered assets	$ 244,782			$ 306,807
Allowance for covered loan losses	(21,733)			(25,939)
Net covered assets	223,049			280,868
Covered Assets [Member]
Commercial loans	25,571			31,568
Commercial real estate loans	113,415			150,210
Residential mortgage loans	46,998			50,403
Consumer installment and other	5,411			6,123
Foreclosed real estate	29,472			30,342
Asset in lieu	11
Estimated loss reimbursement by the FDIC	23,904			38,161
Total covered assets	244,782			306,807
Allowance for covered loan losses	(21,733)		(26,323)	(25,939)		(16,904)	(19,738)	(15,334)
Net covered assets	223,049			280,868
Purchased Impaired Loans [Member] | Covered Assets [Member]
Commercial loans	6,984			10,489
Commercial real estate loans	25,137			38,433
Residential mortgage loans	306			292
Consumer installment and other	291			281
Total covered assets	32,718			49,495
Allowance for covered loan losses	(8,522)		(12,871)	(14,727)		(8,817)	(11,690)	(8,601)
Net covered assets	24,196			34,768
Purchased Nonimpaired Loans [Member] | Covered Assets [Member]
Commercial loans	18,587			21,079
Commercial real estate loans	88,278			111,777
Residential mortgage loans	46,692			50,111
Consumer installment and other	4,831			5,518
Total covered assets	158,388			188,485
Allowance for covered loan losses	(13,211)		(13,452)	(11,212)		(8,087)	(8,048)	(6,733)
Net covered assets	145,177			177,273
Nonperforming covered loans (1)	19,975	[1]		19,894	[1]
Other Assets [Member] | Covered Assets [Member]
Consumer installment and other	289			324
Foreclosed real estate	29,472			30,342
Asset in lieu	11
Estimated loss reimbursement by the FDIC	23,904			38,161
Total covered assets	53,676			68,827
Net covered assets	$ 53,676			$ 68,827

[1] Excludes purchased impaired loans which are accounted for on a pool basis based on common risk characteristics as a single asset with a single composite interest rate and an aggregate expectation of cash flows. Because we are recognizing interest income on each pool of loans, all purchased impaired loans are considered to be performing.