Allowance for Loan Losses (Allowance for Loan Losses Rollforward Analysis) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance, Beginning Balance	$ 30,873	$ 29,802
Charge-offs	(374)	(681)
Recoveries	40	24
Provision	600	900
Allowance, Ending Balance	31,139	30,045
Commercial Mortgages [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance, Beginning Balance	9,407	8,195
Charge-offs	(114)	(9)
Recoveries	6	2
Provision	308	1,164
Allowance, Ending Balance	9,607	9,352
Commercial Construction and Development [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance, Beginning Balance	224	95
Charge-offs	0	0
Recoveries	0	0
Provision	22	15
Allowance, Ending Balance	246	110
Commercial Other [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance, Beginning Balance	5,996	6,200
Charge-offs	(93)	(330)
Recoveries	22	6
Provision	41	30
Allowance, Ending Balance	5,966	5,906
Commercial Segment [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance, Beginning Balance	15,627	14,490
Charge-offs	(207)	(339)
Recoveries	28	8
Provision	371	1,209
Allowance, Ending Balance	15,819	15,368
Residential Segment [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance, Beginning Balance	4,269	4,694
Charge-offs	(9)	(234)
Recoveries	0	10
Provision	273	(145)
Allowance, Ending Balance	4,533	4,325
Consumer Segment [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance, Beginning Balance	2,684	2,452
Charge-offs	(158)	(108)
Recoveries	12	6
Provision	(49)	(217)
Allowance, Ending Balance	2,489	2,133
Unallocated [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance, Beginning Balance	8,293	8,166
Charge-offs
Recoveries
Provision	5	53
Allowance, Ending Balance	$ 8,298	$ 8,219