Allowance for Loan Losses (Allowance for Loan Losses Rollforward Analysis) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning Balance	$ 29,802	$ 28,583	$ 27,400
Charge-offs	(2,335)	(3,834)	(5,402)
Recoveries	706	353	585
Provision	2,700	4,700	6,000
Ending Balance	30,873	29,802	28,583
Commercial Mortgages [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning Balance	8,195	7,330
Charge-offs	(485)	(960)
Recoveries	442	7
Provision	1,255	1,818
Ending Balance	9,407	8,195
Commercial Construction and Development [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning Balance	95	723
Charge-offs	0	0
Recoveries	0	0
Provision	129	(628)
Ending Balance	224	95
Commercial Other [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning Balance	6,200	6,495
Charge-offs	(1,179)	(1,685)
Recoveries	103	311
Provision	872	1,079
Ending Balance	5,996	6,200
Commercial Segment [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning Balance	14,490	14,548
Charge-offs	(1,664)	(2,645)
Recoveries	545	318
Provision	2,256	2,269
Ending Balance	15,627	14,490
Residential Segment [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning Balance	4,694	4,129
Charge-offs	(367)	(641)
Recoveries	110	4
Provision	(168)	1,202
Ending Balance	4,269	4,694
Consumer Segment [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning Balance	2,452	1,903
Charge-offs	(304)	(548)
Recoveries	51	31
Provision	485	1,066
Ending Balance	2,684	2,452
Unallocated [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning Balance	8,166	8,003
Charge-offs
Recoveries
Provision	127	163
Ending Balance	$ 8,293	$ 8,166