Loans Receivable and Allowance for Loan Losses (Schedule of Impaired Loan Receivables) (Details) (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jun. 30, 2013	Dec. 31, 2012
Loans With No Related Allowance:
Recorded Investment	$ 41,337	$ 37,530
Unpaid Principal Balance	48,000	45,136
Loans With An Allowance Recorded:
Recorded Investment	22,331	19,111
Unpaid Principal Balance	22,331	19,982
Total Impaired Loans:
Recorded Investment	63,668	56,641
Unpaid Principal Balance	70,331	65,118
Related Allowance	10,335	7,120
Proceeds from Collections of Impaired Financing Receivable	2,900
Commercial and industrial [Member]
Loans With No Related Allowance:
Recorded Investment	10,101	7,426
Unpaid Principal Balance	15,253	11,746
Loans With An Allowance Recorded:
Recorded Investment	5,305	5,656
Unpaid Principal Balance	5,305	6,526
Total Impaired Loans:
Recorded Investment	15,406	13,082
Unpaid Principal Balance	20,558	18,272
Related Allowance	2,695	2,399
Commercial tax-exempt [Member]
Loans With No Related Allowance:
Recorded Investment	0	0
Unpaid Principal Balance	0	0
Total Impaired Loans:
Recorded Investment	0	0
Unpaid Principal Balance	0	0
Related Allowance	0	0
Owner occupied real estate [Member]
Loans With No Related Allowance:
Recorded Investment	3,845	1,929
Unpaid Principal Balance	4,448	2,301
Loans With An Allowance Recorded:
Recorded Investment	1,415	1,451
Unpaid Principal Balance	1,415	1,451
Total Impaired Loans:
Recorded Investment	5,260	3,380
Unpaid Principal Balance	5,863	3,752
Related Allowance	1,415	1,451
Commercial construction and land development [Member]
Loans With No Related Allowance:
Recorded Investment	7,717	7,716
Unpaid Principal Balance	7,863	8,500
Loans With An Allowance Recorded:
Recorded Investment	7,809	7,833
Unpaid Principal Balance	7,809	7,833
Total Impaired Loans:
Recorded Investment	15,526	15,549
Unpaid Principal Balance	15,672	16,333
Related Allowance	3,470	2,470
Commercial real estate [Member]
Loans With No Related Allowance:
Recorded Investment	11,173	12,965
Unpaid Principal Balance	11,329	14,619
Loans With An Allowance Recorded:
Recorded Investment	4,157	4,171
Unpaid Principal Balance	4,157	4,172
Total Impaired Loans:
Recorded Investment	15,330	17,136
Unpaid Principal Balance	15,486	18,791
Related Allowance	1,755	800
Residential [Member]
Loans With No Related Allowance:
Recorded Investment	5,130	4,163
Unpaid Principal Balance	5,482	4,423
Loans With An Allowance Recorded:
Recorded Investment	3,153	0
Unpaid Principal Balance	3,153	0
Total Impaired Loans:
Recorded Investment	8,283	4,163
Unpaid Principal Balance	8,635	4,423
Related Allowance	508	0
Consumer [Member]
Loans With No Related Allowance:
Recorded Investment	3,371	3,331
Unpaid Principal Balance	3,625	3,547
Loans With An Allowance Recorded:
Recorded Investment	492	0
Unpaid Principal Balance	492	0
Total Impaired Loans:
Recorded Investment	3,863	3,331
Unpaid Principal Balance	4,117	3,547
Related Allowance	492	0
No Transition From Prior Year [Member]
Loans With No Related Allowance:
Recorded Investment	32,800
Loans With An Allowance Recorded:
Recorded Investment	16,600
Downgraded as Impaired During the Period [Member]
Loans With An Allowance Recorded:
Recorded Investment	5,900
Total Impaired Loans:
Recorded Investment	15,200
Charged Off [Member]
Total Impaired Loans:
Proceeds from Collections of Impaired Financing Receivable	851
Transferred to Foreclosed Real Estate [Member]
Total Impaired Loans:
Proceeds from Collections of Impaired Financing Receivable	$ 2,600