COVERED ASSETS AND FDIC INDEMNIFICATION ASSET (Details 4) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012
Carrying Amounts And Composition Of Covered Loans
Total principal balance	$ 3,217,341	$ 3,450,956
Pass/Watch
Carrying Amounts And Composition Of Covered Loans
Total principal balance	2,424,681	2,569,918
Special Mention
Carrying Amounts And Composition Of Covered Loans
Total principal balance	56,372	58,016
Substandard
Carrying Amounts And Composition Of Covered Loans
Total principal balance	728,194	814,814
Doubtful
Carrying Amounts And Composition Of Covered Loans
Total principal balance	8,094	8,208
Real Estate Loans
Carrying Amounts And Composition Of Covered Loans
Total principal balance	2,594,243	2,775,972
Real Estate Loans | Pass/Watch
Carrying Amounts And Composition Of Covered Loans
Total principal balance	1,941,693	2,050,246
Real Estate Loans | Special Mention
Carrying Amounts And Composition Of Covered Loans
Total principal balance	31,300	34,968
Real Estate Loans | Substandard
Carrying Amounts And Composition Of Covered Loans
Total principal balance	613,351	682,745
Real Estate Loans | Doubtful
Carrying Amounts And Composition Of Covered Loans
Total principal balance	7,899	8,013
Real Estate Loans | Residential Single-family
Carrying Amounts And Composition Of Covered Loans
Total principal balance	341,946	362,345
Real Estate Loans | Residential Single-family | Pass/Watch
Carrying Amounts And Composition Of Covered Loans
Total principal balance	325,397	345,568
Real Estate Loans | Residential Single-family | Special Mention
Carrying Amounts And Composition Of Covered Loans
Total principal balance	903	982
Real Estate Loans | Residential Single-family | Substandard
Carrying Amounts And Composition Of Covered Loans
Total principal balance	15,646	15,795
Real Estate Loans | Residential Multifamily
Carrying Amounts And Composition Of Covered Loans
Total principal balance	587,409	647,440
Real Estate Loans | Residential Multifamily | Pass/Watch
Carrying Amounts And Composition Of Covered Loans
Total principal balance	526,181	571,061
Real Estate Loans | Residential Multifamily | Special Mention
Carrying Amounts And Composition Of Covered Loans
Total principal balance	6,262	8,074
Real Estate Loans | Residential Multifamily | Substandard
Carrying Amounts And Composition Of Covered Loans
Total principal balance	54,966	68,305
Real Estate Loans | Commercial and Industrial Real Estate
Carrying Amounts And Composition Of Covered Loans
Total principal balance	1,279,779	1,348,556
Real Estate Loans | Commercial and Industrial Real Estate | Pass/Watch
Carrying Amounts And Composition Of Covered Loans
Total principal balance	934,102	963,069
Real Estate Loans | Commercial and Industrial Real Estate | Special Mention
Carrying Amounts And Composition Of Covered Loans
Total principal balance	9,343	10,777
Real Estate Loans | Commercial and Industrial Real Estate | Substandard
Carrying Amounts And Composition Of Covered Loans
Total principal balance	329,607	367,869
Real Estate Loans | Commercial and Industrial Real Estate | Doubtful
Carrying Amounts And Composition Of Covered Loans
Total principal balance	6,727	6,841
Real Estate Loans | Construction and Land
Carrying Amounts And Composition Of Covered Loans
Total principal balance	385,109	417,631
Real Estate Loans | Construction and Land | Pass/Watch
Carrying Amounts And Composition Of Covered Loans
Total principal balance	156,013	170,548
Real Estate Loans | Construction and Land | Special Mention
Carrying Amounts And Composition Of Covered Loans
Total principal balance	14,792	15,135
Real Estate Loans | Construction and Land | Substandard
Carrying Amounts And Composition Of Covered Loans
Total principal balance	213,132	230,776
Real Estate Loans | Construction and Land | Doubtful
Carrying Amounts And Composition Of Covered Loans
Total principal balance	1,172	1,172
Other Loans
Carrying Amounts And Composition Of Covered Loans
Total principal balance	623,098	674,984
Other Loans | Pass/Watch
Carrying Amounts And Composition Of Covered Loans
Total principal balance	482,988	519,672
Other Loans | Special Mention
Carrying Amounts And Composition Of Covered Loans
Total principal balance	25,072	23,048
Other Loans | Substandard
Carrying Amounts And Composition Of Covered Loans
Total principal balance	114,843	132,069
Other Loans | Doubtful
Carrying Amounts And Composition Of Covered Loans
Total principal balance	195	195
Other Loans | Commercial Business
Carrying Amounts And Composition Of Covered Loans
Total principal balance	539,481	587,333
Other Loans | Commercial Business | Pass/Watch
Carrying Amounts And Composition Of Covered Loans
Total principal balance	401,191	434,138
Other Loans | Commercial Business | Special Mention
Carrying Amounts And Composition Of Covered Loans
Total principal balance	24,793	22,533
Other Loans | Commercial Business | Substandard
Carrying Amounts And Composition Of Covered Loans
Total principal balance	113,302	130,467
Other Loans | Commercial Business | Doubtful
Carrying Amounts And Composition Of Covered Loans
Total principal balance	195	195
Other Loans | Other Consumer
Carrying Amounts And Composition Of Covered Loans
Total principal balance	83,617	87,651
Other Loans | Other Consumer | Pass/Watch
Carrying Amounts And Composition Of Covered Loans
Total principal balance	81,797	85,534
Other Loans | Other Consumer | Special Mention
Carrying Amounts And Composition Of Covered Loans
Total principal balance	279	515
Other Loans | Other Consumer | Substandard
Carrying Amounts And Composition Of Covered Loans
Total principal balance	$ 1,541	$ 1,602