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, 2013	Dec. 31, 2012
Financing Receivable, Recorded Investment [Line Items]
Nonaccrual loans	$ 43,527	$ 32,416
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	24,384	14,966
Commercial and industrial [Member]
Financing Receivable, Recorded Investment [Line Items]
Nonaccrual loans	12,053	11,289
Loans receivable, equal to greater than 90 days past due	4,530	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	4,999	3,119
Loans receivable, equal to greater than 90 days past due	3,166	1,592
Commercial construction and land development [Member]
Financing Receivable, Recorded Investment [Line Items]
Nonaccrual loans	12,027	6,300
Loans receivable, equal to greater than 90 days past due	8,338	2,580
Commercial real estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Nonaccrual loans	3,893	5,659
Loans receivable, equal to greater than 90 days past due	786	3,659
Residential [Member]
Financing Receivable, Recorded Investment [Line Items]
Nonaccrual loans	7,133	3,203
Loans receivable, equal to greater than 90 days past due	5,772	1,757
Consumer [Member]
Financing Receivable, Recorded Investment [Line Items]
Nonaccrual loans	3,422	2,846
Loans receivable, equal to greater than 90 days past due	$ 1,792	$ 1,511