Allowance for Noncovered Loan and Lease Losses and Unfunded Commitments and Letters of Credit (Analysis of Credit Quality of Noncovered Loan Portfolio) (Details) (Noncovered Loans [Member], USD $) In Thousands, unless otherwise specified	6 Months Ended	12 Months Ended
	Jun. 30, 2012 risk_rating	Dec. 31, 2011 risk_rating
Accounts, Notes, Loans and Financing Receivable [Line Items]
Recorded Investment	$ 2,436,961	$ 2,348,371
Commercial Portfolio Segment [Member] | Secured Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Weighted Average Risk Rating	4.87	4.89
Recorded Investment	1,062,863	981,417
Commercial Portfolio Segment [Member] | Unsecured Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Weighted Average Risk Rating	4.31	4.25
Recorded Investment	45,273	47,406
Real Estate Portfolio Segment [Member] | One-to-Four Family Residential [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Weighted Average Risk Rating	4.73	4.81
Recorded Investment	56,015	64,063
Real Estate Portfolio Segment [Member] | Commercial Land [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Weighted Average Risk Rating	5.12	5.22
Recorded Investment	44,886	50,681
Real Estate Portfolio Segment [Member] | Income Property Multifamily [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Weighted Average Risk Rating	4.85	4.94
Recorded Investment	580,029	533,993
Real Estate Portfolio Segment [Member] | Owner Occupied [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Weighted Average Risk Rating	5.05	5.05
Recorded Investment	384,971	404,789
Real Estate Construction Portfolio Segment [Member] | Income Property Multifamily [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Weighted Average Risk Rating	4.89	5.49
Recorded Investment	26,568	20,877
Real Estate Construction Portfolio Segment [Member] | Owner Occupied [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Weighted Average Risk Rating	4.59	4.55
Recorded Investment	22,122	12,790
Real Estate Construction Portfolio Segment [Member] | Land and Acquisition [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Weighted Average Risk Rating	6.08	6.43
Recorded Investment	20,556	25,201
Real Estate Construction Portfolio Segment [Member] | Residential Construction [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Weighted Average Risk Rating	5.74	5.94
Recorded Investment	26,224	23,931
Consumer Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Weighted Average Risk Rating	4.22	4.24
Recorded Investment	$ 167,454	$ 183,223