Loans Receivable and Allowance for Loan Losses (Summary of Nonaccrual Loans, by Type) (Details) (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jun. 30, 2012 Nonaccrual_Loans	Dec. 31, 2011
Financing Receivable, Recorded Investment [Line Items]
Nonaccrual loans	$ 35,438	$ 34,129
Period used to determine when a loan receivable is moved to nonaccrual status	90 days
Loans receivable, equal to greater than 90 days past due	20,717	23,370
Amount available to be advanced on nonaccrual loans	9
Number of nonaccrual loans with funds available for advance	1
Commercial and industrial [Member]
Financing Receivable, Recorded Investment [Line Items]
Nonaccrual loans	16,631	10,162
Loans receivable, equal to greater than 90 days past due	6,997	3,193
Commercial tax-exempt [Member]
Financing Receivable, Recorded Investment [Line Items]
Nonaccrual loans	0	0
Loans receivable, equal to greater than 90 days past due	0	0
Owner occupied real estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Nonaccrual loans	3,275	2,895
Loans receivable, equal to greater than 90 days past due	3,172	1,901
Commercial construction and land development [Member]
Financing Receivable, Recorded Investment [Line Items]
Nonaccrual loans	4,002	8,511
Loans receivable, equal to greater than 90 days past due	3,606	8,304
Commercial real estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Nonaccrual loans	6,174	7,820
Loans receivable, equal to greater than 90 days past due	3,883	6,124
Residential [Member]
Financing Receivable, Recorded Investment [Line Items]
Nonaccrual loans	3,233	2,912
Loans receivable, equal to greater than 90 days past due	1,985	2,905
Consumer [Member]
Financing Receivable, Recorded Investment [Line Items]
Nonaccrual loans	2,123	1,829
Loans receivable, equal to greater than 90 days past due	$ 1,074	$ 943