Loans Receivable and Allowance for Loan Losses (Summary of Nonaccrual Loans, by Type) (Details) (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Sep. 30, 2013 Nonaccrual_Loans	Dec. 31, 2012
Financing Receivable, Recorded Investment [Line Items]
Period used to determine when a loan receivable is moved to nonaccrual status	90 days
Nonaccrual loans	$ 43,375	$ 32,416
Loans receivable, equal to greater than 90 days past due	19,390	14,966
Number of loans placed on nonaccrual status	1
Nonaccrual loans, unused commitment	132
Commercial and industrial [Member]
Financing Receivable, Recorded Investment [Line Items]
Nonaccrual loans	9,967	11,289
Loans receivable, equal to greater than 90 days past due	4,934	3,867
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	4,924	3,119
Loans receivable, equal to greater than 90 days past due	3,403	1,592
Commercial construction and land development [Member]
Financing Receivable, Recorded Investment [Line Items]
Nonaccrual loans	11,723	6,300
Loans receivable, equal to greater than 90 days past due	8,074	2,580
Commercial real estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Nonaccrual loans	6,904	5,659
Loans receivable, equal to greater than 90 days past due	578	3,659
Residential [Member]
Financing Receivable, Recorded Investment [Line Items]
Nonaccrual loans	7,316	3,203
Loans receivable, equal to greater than 90 days past due	1,540	1,757
Consumer [Member]
Financing Receivable, Recorded Investment [Line Items]
Nonaccrual loans	2,541	2,846
Loans receivable, equal to greater than 90 days past due	$ 861	$ 1,511