COVERED ASSETS AND FDIC INDEMNIFICATION ASSET (Details 2) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012	Dec. 31, 2011
Carrying Amounts And Composition Of Covered Loans
Total principal balance	$ 3,767,007	$ 4,718,084
Covered discount	(582,545)	(788,295)
Net valuation of loans	3,184,462	3,929,789
Allowance on covered loans	(5,877)	(6,647)
Total covered loans, net	3,178,585	3,923,142
Pass/Watch
Carrying Amounts And Composition Of Covered Loans
Total principal balance	2,732,683	3,439,848
Special Mention
Carrying Amounts And Composition Of Covered Loans
Total principal balance	83,923	146,585
Substandard
Carrying Amounts And Composition Of Covered Loans
Total principal balance	941,748	1,112,568
Doubtful
Carrying Amounts And Composition Of Covered Loans
Total principal balance	8,653	19,083
Real Estate Loans
Carrying Amounts And Composition Of Covered Loans
Total principal balance	3,046,033	3,788,478
Real Estate Loans | Pass/Watch
Carrying Amounts And Composition Of Covered Loans
Total principal balance	2,200,451	2,700,389
Real Estate Loans | Special Mention
Carrying Amounts And Composition Of Covered Loans
Total principal balance	53,336	111,878
Real Estate Loans | Substandard
Carrying Amounts And Composition Of Covered Loans
Total principal balance	784,126	961,813
Real Estate Loans | Doubtful
Carrying Amounts And Composition Of Covered Loans
Total principal balance	8,120	14,398
Real Estate Loans | Residential Single-family
Carrying Amounts And Composition Of Covered Loans
Total principal balance	385,287	442,732
Real Estate Loans | Residential Single-family | Pass/Watch
Carrying Amounts And Composition Of Covered Loans
Total principal balance	366,326	427,918
Real Estate Loans | Residential Single-family | Special Mention
Carrying Amounts And Composition Of Covered Loans
Total principal balance	2,079	1,085
Real Estate Loans | Residential Single-family | Substandard
Carrying Amounts And Composition Of Covered Loans
Total principal balance	16,882	13,729
Real Estate Loans | Residential Multifamily
Carrying Amounts And Composition Of Covered Loans
Total principal balance	721,775	918,941
Real Estate Loans | Residential Multifamily | Pass/Watch
Carrying Amounts And Composition Of Covered Loans
Total principal balance	621,633	779,694
Real Estate Loans | Residential Multifamily | Special Mention
Carrying Amounts And Composition Of Covered Loans
Total principal balance	12,272	26,124
Real Estate Loans | Residential Multifamily | Substandard
Carrying Amounts And Composition Of Covered Loans
Total principal balance	87,870	113,123
Real Estate Loans | Commercial and Industrial Real Estate
Carrying Amounts And Composition Of Covered Loans
Total principal balance	1,480,742	1,773,760
Real Estate Loans | Commercial and Industrial Real Estate | Pass/Watch
Carrying Amounts And Composition Of Covered Loans
Total principal balance	1,033,938	1,249,781
Real Estate Loans | Commercial and Industrial Real Estate | Special Mention
Carrying Amounts And Composition Of Covered Loans
Total principal balance	8,214	43,810
Real Estate Loans | Commercial and Industrial Real Estate | Substandard
Carrying Amounts And Composition Of Covered Loans
Total principal balance	431,691	472,003
Real Estate Loans | Commercial and Industrial Real Estate | Doubtful
Carrying Amounts And Composition Of Covered Loans
Total principal balance	6,899	8,166
Real Estate Loans | Construction and Land
Carrying Amounts And Composition Of Covered Loans
Total principal balance	458,229	653,045
Real Estate Loans | Construction and Land | Pass/Watch
Carrying Amounts And Composition Of Covered Loans
Total principal balance	178,554	242,996
Real Estate Loans | Construction and Land | Special Mention
Carrying Amounts And Composition Of Covered Loans
Total principal balance	30,771	40,859
Real Estate Loans | Construction and Land | Substandard
Carrying Amounts And Composition Of Covered Loans
Total principal balance	247,683	362,958
Real Estate Loans | Construction and Land | Doubtful
Carrying Amounts And Composition Of Covered Loans
Total principal balance	1,221	6,232
Other Loans
Carrying Amounts And Composition Of Covered Loans
Total principal balance	720,974	929,606
Other Loans | Pass/Watch
Carrying Amounts And Composition Of Covered Loans
Total principal balance	532,232	739,459
Other Loans | Special Mention
Carrying Amounts And Composition Of Covered Loans
Total principal balance	30,587	34,707
Other Loans | Substandard
Carrying Amounts And Composition Of Covered Loans
Total principal balance	157,622	150,755
Other Loans | Doubtful
Carrying Amounts And Composition Of Covered Loans
Total principal balance	533	4,685
Other Loans | Commercial Business
Carrying Amounts And Composition Of Covered Loans
Total principal balance	632,292	831,762
Other Loans | Commercial Business | Pass/Watch
Carrying Amounts And Composition Of Covered Loans
Total principal balance	445,844	643,117
Other Loans | Commercial Business | Special Mention
Carrying Amounts And Composition Of Covered Loans
Total principal balance	30,587	34,707
Other Loans | Commercial Business | Substandard
Carrying Amounts And Composition Of Covered Loans
Total principal balance	155,328	149,253
Other Loans | Commercial Business | Doubtful
Carrying Amounts And Composition Of Covered Loans
Total principal balance	533	4,685
Other Loans | Other Consumer
Carrying Amounts And Composition Of Covered Loans
Total principal balance	88,682	97,844
Other Loans | Other Consumer | Pass/Watch
Carrying Amounts And Composition Of Covered Loans
Total principal balance	86,388	96,342
Other Loans | Other Consumer | Substandard
Carrying Amounts And Composition Of Covered Loans
Total principal balance	$ 2,294	$ 1,502