Allowance for Loan and Lease Losses and Unfunded Loan Commitments and Letters of Credit (Analysis of Credit Quality of Noncovered Loan Portfolio) (Details) (USD $) In Thousands, unless otherwise specified	9 Months Ended	12 Months Ended
	Sep. 30, 2011	Dec. 31, 2010
Recorded Investment Noncovered Loans	$ 2,257,899	$ 1,927,191
Commercial Business [Member] | Secured Debt [Member]
Weighted-Average Risk Rating	4.95	4.96
Recorded Investment Noncovered Loans	916,290	757,372
Commercial Business [Member] | Unsecured Debt [Member]
Weighted-Average Risk Rating	4.25	4.23
Recorded Investment Noncovered Loans	58,836	41,175
Real Estate One-To-Four Family [Member] | Residential [Member]
Weighted-Average Risk Rating	4.91	4.96
Recorded Investment Noncovered Loans	63,672	49,436
Real Estate Commercial & Multifamily Residential [Member] | Commercial Land [Member]
Weighted-Average Risk Rating	5.64	5.75
Recorded Investment Noncovered Loans	48,132	24,956
Real Estate Commercial & Multifamily Residential [Member] | Income Property Multifamily [Member]
Weighted-Average Risk Rating	4.98	5.07
Recorded Investment Noncovered Loans	526,531	406,711
Real Estate Commercial & Multifamily Residential [Member] | Owner Occupied [Member]
Weighted-Average Risk Rating	5.08	5.12
Recorded Investment Noncovered Loans	391,804	366,284
Construction One-To-Four Family Residential[Member] | Land and Acquisition [Member]
Weighted-Average Risk Rating	6.61	6.79
Recorded Investment Noncovered Loans	25,978	37,054
Construction One-To-Four Family Residential[Member] | Residential Construction [Member]
Weighted-Average Risk Rating	6.07	6.63
Recorded Investment Noncovered Loans	25,945	31,293
Construction Commercial & Multifamily Residential [Member] | Income Property Multifamily [Member]
Weighted-Average Risk Rating	5.39	6.38
Recorded Investment Noncovered Loans	13,801	18,296
Construction Commercial & Multifamily Residential [Member] | Owner Occupied [Member]
Weighted-Average Risk Rating	4.45	4.93
Recorded Investment Noncovered Loans	10,358	11,990
Consumer [Member]
Weighted-Average Risk Rating	4.27	4.31
Recorded Investment Noncovered Loans	$ 176,552	$ 182,624