Loans Receivable and Allowance for Loan Losses (Summary of Nonaccrual Loans, by Type) (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2015	Dec. 31, 2014
Financing Receivable, Recorded Investment [Line Items]
Period used to determine when a loan receivable is moved to nonaccrual status	90 days
Nonaccrual loans	$ 36,212	$ 34,966
Total past due loans	45,215	34,628
Nonaccrual loans, unused commitment	$ 0
Period used to analyze future loan losses	2 years
Commercial and industrial [Member]
Financing Receivable, Recorded Investment [Line Items]
Nonaccrual loans	$ 10,850	11,634
Total past due loans	11,390	10,699
Commercial tax-exempt [Member]
Financing Receivable, Recorded Investment [Line Items]
Nonaccrual loans	0	0
Total past due loans	0	0
Owner occupied real estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Nonaccrual loans	9,290	7,416
Total past due loans	10,577	6,389
Commercial construction and land development [Member]
Financing Receivable, Recorded Investment [Line Items]
Nonaccrual loans	3,017	3,228
Total past due loans	6,148	801
Commercial real estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Nonaccrual loans	6,722	5,824
Total past due loans	8,680	2,893
Residential [Member]
Financing Receivable, Recorded Investment [Line Items]
Nonaccrual loans	5,133	4,987
Total past due loans	4,097	9,718
Consumer [Member]
Financing Receivable, Recorded Investment [Line Items]
Nonaccrual loans	1,200	1,877
Total past due loans	4,323	4,128
Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Financing Receivable, Recorded Investment [Line Items]
Total past due loans	27,473	16,872
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Commercial and industrial [Member]
Financing Receivable, Recorded Investment [Line Items]
Total past due loans	10,672	5,727
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Commercial tax-exempt [Member]
Financing Receivable, Recorded Investment [Line Items]
Total past due loans	0	0
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Owner occupied real estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Total past due loans	7,602	5,739
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Commercial construction and land development [Member]
Financing Receivable, Recorded Investment [Line Items]
Total past due loans	30	0
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Commercial real estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Total past due loans	5,664	1,614
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Residential [Member]
Financing Receivable, Recorded Investment [Line Items]
Total past due loans	2,792	2,751
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Consumer [Member]
Financing Receivable, Recorded Investment [Line Items]
Total past due loans	$ 713	$ 1,041