Estimated Fair Value Of Financial Instruments (Fair Value Measurements On A Nonrecurring Basis) (Detail) (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jun. 30, 2012		Jun. 30, 2011
Estimated Fair Value Of Financial Instruments [Line Items]
Collateral-dependent impaired loans, Fair Value	$ 83,980	[1]	$ 175,411	[1]
Covered assets-OREO, Fair Value	9,934	[2],[3]	5,455	[2],[3]
OREO, Fair Value	57,431	[2]	40,567	[2]
Total, Fair Value	151,345		221,433
Collateral-dependent impaired loans, Losses	22,132	[1]	33,615	[1]
Covered assets - OREO, Losses	859	[2],[3]	658	[2],[3]
OREO, Losses	13,729	[3]	10,245	[3]
Total, Losses	$ 36,720		$ 44,518
Portion of the write-down not reimbursed by FDIC	20.00%

[1] Represents the fair value of loans adjusted to the appraised value of the collateral with a write-down in fair value or change in specific reserves during the respective period. These fair value adjustments are recognized as part of the provision for loan losses charged to earnings.

[2] Represents the fair value of foreclosed properties that were adjusted subsequent to their initial classification as foreclosed assets. Write-downs are recognized as a component of net foreclosed real estate expense in the Consolidated Statements of Income.

[3] The 20% portion of any covered asset OREO write-down not reimbursed by the FDIC is recorded as net foreclosed real estate expense.