Loans Receivable and Allowance for Loan Losses (Schedule of Impaired Loan Receivables, Average) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Loans With No Related Allowance:
Average Recorded Investment	$ 43,380	$ 41,026	$ 46,122	$ 48,014
Interest Income Recognized	252	73	582	380
Loans With An Allowance Recorded:
Average Recorded Investment	18,987	12,738	17,212	13,342
Interest Income Recognized	0	0	0	0
Total Impaired Loans:
Average Recorded Investment	62,367	53,764	63,334	61,356
Interest Income Recognized	252	73	582	380
Period used to determine when loan receivables are past due			90 days
Commercial and industrial [Member]
Loans With No Related Allowance:
Average Recorded Investment	11,321	13,566	12,103	16,717
Interest Income Recognized	31	4	92	90
Loans With An Allowance Recorded:
Average Recorded Investment	4,219	8,634	3,010	8,742
Interest Income Recognized	0	0	0	0
Total Impaired Loans:
Average Recorded Investment	15,540	22,200	15,113	25,459
Interest Income Recognized	31	4	92	90
Commercial tax-exempt [Member]
Loans With No Related Allowance:
Average Recorded Investment	0	0	0	0
Interest Income Recognized	0	0	0	0
Total Impaired Loans:
Average Recorded Investment	0	0	0	0
Interest Income Recognized	0	0	0	0
Owner occupied real estate [Member]
Loans With No Related Allowance:
Average Recorded Investment	4,306	4,156	5,508	5,759
Interest Income Recognized	43	30	123	100
Loans With An Allowance Recorded:
Average Recorded Investment	1,456	739	1,136	743
Interest Income Recognized	0	0	0	0
Total Impaired Loans:
Average Recorded Investment	5,762	4,895	6,644	6,502
Interest Income Recognized	43	30	123	100
Commercial construction and land development [Member]
Loans With No Related Allowance:
Average Recorded Investment	10,680	10,148	11,161	12,096
Interest Income Recognized	130	2	251	115
Loans With An Allowance Recorded:
Average Recorded Investment	13,312	3,365	13,066	3,857
Interest Income Recognized		0	0	0
Total Impaired Loans:
Average Recorded Investment	23,992	13,513	24,227	15,953
Interest Income Recognized	130	2	251	115
Commercial real estate [Member]
Loans With No Related Allowance:
Average Recorded Investment	10,842	7,209	11,429	7,509
Interest Income Recognized	39	37	96	75
Total Impaired Loans:
Average Recorded Investment	10,842	7,209	11,429	7,509
Interest Income Recognized	39	37	96	75
Residential [Member]
Loans With No Related Allowance:
Average Recorded Investment	3,963	3,674	3,785	3,784
Interest Income Recognized	7	0	18	0
Total Impaired Loans:
Average Recorded Investment	3,963	3,674	3,785	3,784
Interest Income Recognized	7	0	18	0
Consumer [Member]
Loans With No Related Allowance:
Average Recorded Investment	2,268	2,273	2,136	2,149
Interest Income Recognized	2	0	2	0
Total Impaired Loans:
Average Recorded Investment	2,268	2,273	2,136	2,149
Interest Income Recognized	$ 2	$ 0	$ 2	$ 0