Allowance for Loan Losses (Allowance for Loan Losses Rollforward Analysis) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance, Beginning Balance	$ 30,448	$ 29,353	$ 29,802	$ 28,583
Charge-offs	(424)	(818)	(1,801)	(2,914)
Recoveries	128	106	651	272
Provision	600	1,000	2,100	3,700
Allowance, Ending Balance	30,752	29,641	30,752	29,641
Commercial Mortgages [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance, Beginning Balance	8,945	7,374	8,195	7,330
Charge-offs	(258)	(250)	(267)	(709)
Recoveries	46	1	436	5
Provision	520	478	889	977
Allowance, Ending Balance	9,253	7,603	9,253	7,603
Commercial Construction and Development [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance, Beginning Balance	164	217	95	723
Charge-offs	0	0	0	0
Recoveries	0	0	0	0
Provision	54	(34)	123	(540)
Allowance, Ending Balance	218	183	218	183
Commercial Other [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance, Beginning Balance	6,239	6,993	6,200	6,495
Charge-offs	(15)	(378)	(925)	(1,573)
Recoveries	37	92	74	238
Provision	245	(171)	1,157	1,376
Allowance, Ending Balance	6,506	6,536	6,506	6,536
Commercial Segment [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance, Beginning Balance	15,348	14,584	14,490	14,548
Charge-offs	(273)	(628)	(1,192)	(2,282)
Recoveries	83	93	510	243
Provision	819	273	2,169	1,813
Allowance, Ending Balance	15,977	14,322	15,977	14,322
Residential Segment [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance, Beginning Balance	4,713	4,471	4,694	4,129
Charge-offs	(65)	(103)	(315)	(368)
Recoveries	24	3	97	4
Provision	(408)	484	(212)	1,090
Allowance, Ending Balance	4,264	4,855	4,264	4,855
Consumer Segment [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance, Beginning Balance	2,381	2,152	2,452	1,903
Charge-offs	(86)	(87)	(294)	(264)
Recoveries	21	10	44	25
Provision	323	315	437	726
Allowance, Ending Balance	2,639	2,390	2,639	2,390
Unallocated [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance, Beginning Balance	8,006	8,146	8,166	8,003
Charge-offs	0	0	0	0
Recoveries	0	0	0	0
Provision	(134)	(72)	(294)	71
Allowance, Ending Balance	$ 7,872	$ 8,074	$ 7,872	$ 8,074