Basis Of Presentation And Accounting Policies (Valuation Methodologies For Instruments Measured At Fair Value On Nonrecurring Basis) (Detail) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2012	Dec. 31, 2011	Jun. 30, 2011
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Covered loans	$ 601,737	$ 571,489	$ 486,489
Fair Value Measurements on a Nonrecurring Basis
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Impaired loans carried at fair value	60,277	70,296	60,545
Other real estate owned	40,018	50,301	61,533
Covered loans	601,737	571,489	486,489
Covered other real estate owned	83,467	78,617	63,583
Total non-recurring assets at fair value	785,499	770,703	672,150
Level 2 | Fair Value Measurements on a Nonrecurring Basis
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Impaired loans carried at fair value	60,277	70,296	60,545
Total non-recurring assets at fair value	60,277	70,296	60,545
Level 3 | Fair Value Measurements on a Nonrecurring Basis
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Other real estate owned	40,018	50,301	61,533
Covered loans	601,737	571,489	486,489
Covered other real estate owned	83,467	78,617	63,583
Total non-recurring assets at fair value	$ 725,222	$ 700,407	$ 611,605