Loans and the Allowance for Credit Losses (Details 1) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Summary of changes in the allowance for credit losses
Allowance for loan losses, beginning balance	$ 52,699	$ 54,810
Allowance for loan commitments, beginning balance	341	468
Total beginning allowance for credit losses	53,040	55,278
Provision for loan losses	1,997	6,202
Provision for loan commitments	105
Total provision for credit losses	2,102	6,202
Charge-offs	(3,744)	(7,244)
Recoveries	712	627
Net charge-offs	(3,032)	(6,617)
Allowance for loan losses, ending balance	51,664	54,395
Allowance for loan commitments, ending balance	446	468
Total ending allowance for credit losses	52,110	54,863
Commercial Real Estate - Land and Construction [Member]
Summary of changes in the allowance for credit losses
Allowance for loan losses, beginning balance	3,741	4,842
Allowance for loan commitments, beginning balance	27	74
Total beginning allowance for credit losses	3,768	4,916
Provision for loan losses	252	1,670
Provision for loan commitments	5	(21)
Total provision for credit losses	257	1,649
Charge-offs	(51)	(2,117)
Recoveries	3	36
Net charge-offs	(48)	(2,081)
Allowance for loan losses, ending balance	3,945	4,431
Allowance for loan commitments, ending balance	32	53
Total ending allowance for credit losses	3,977	4,484
Commercial Real Estate - Improved Property [Member]
Summary of changes in the allowance for credit losses
Allowance for loan losses, beginning balance	23,614	24,748
Allowance for loan commitments, beginning balance	25	21
Total beginning allowance for credit losses	23,639	24,769
Provision for loan losses	342	1,948
Provision for loan commitments		(15)
Total provision for credit losses	342	1,933
Charge-offs	(995)	(1,885)
Recoveries	228	88
Net charge-offs	(767)	(1,797)
Allowance for loan losses, ending balance	23,189	24,899
Allowance for loan commitments, ending balance	25	6
Total ending allowance for credit losses	23,214	24,905
Commercial & Industrial [Member]
Summary of changes in the allowance for credit losses
Allowance for loan losses, beginning balance	9,326	11,414
Allowance for loan commitments, beginning balance	215	323
Total beginning allowance for credit losses	9,541	11,737
Provision for loan losses	606	386
Provision for loan commitments	89	23
Total provision for credit losses	695	409
Charge-offs	(650)	(761)
Recoveries	107	92
Net charge-offs	(543)	(669)
Allowance for loan losses, ending balance	9,389	11,131
Allowance for loan commitments, ending balance	304	346
Total ending allowance for credit losses	9,693	11,477
Residential Real Estate [Member]
Summary of changes in the allowance for credit losses
Allowance for loan losses, beginning balance	7,182	5,638
Allowance for loan commitments, beginning balance	6	4
Total beginning allowance for credit losses	7,188	5,642
Provision for loan losses	285	835
Provision for loan commitments	3
Total provision for credit losses	288	835
Charge-offs	(553)	(851)
Recoveries	38	87
Net charge-offs	(515)	(764)
Allowance for loan losses, ending balance	6,952	5,709
Allowance for loan commitments, ending balance	9	4
Total ending allowance for credit losses	6,961	5,713
Home Equity [Member]
Summary of changes in the allowance for credit losses
Allowance for loan losses, beginning balance	2,458	1,962
Allowance for loan commitments, beginning balance	49	33
Total beginning allowance for credit losses	2,507	1,995
Provision for loan losses	188	641
Provision for loan commitments	8	11
Total provision for credit losses	196	652
Charge-offs	(176)	(335)
Recoveries	5	4
Net charge-offs	(171)	(331)
Allowance for loan losses, ending balance	2,475	2,272
Allowance for loan commitments, ending balance	57	44
Total ending allowance for credit losses	2,532	2,316
Consumer [Member]
Summary of changes in the allowance for credit losses
Allowance for loan losses, beginning balance	5,557	5,410
Allowance for loan commitments, beginning balance	19	13
Total beginning allowance for credit losses	5,576	5,423
Provision for loan losses	464	893
Provision for loan commitments		2
Total provision for credit losses	464	895
Charge-offs	(1,129)	(1,115)
Recoveries	269	226
Net charge-offs	(860)	(889)
Allowance for loan losses, ending balance	5,161	5,414
Allowance for loan commitments, ending balance	19	15
Total ending allowance for credit losses	5,180	5,429
Deposit Overdraft [Member]
Summary of changes in the allowance for credit losses
Allowance for loan losses, beginning balance	821	796
Allowance for loan commitments, beginning balance
Total beginning allowance for credit losses	821	796
Provision for loan losses	(140)	(171)
Provision for loan commitments
Total provision for credit losses	(140)	(171)
Charge-offs	(190)	(180)
Recoveries	62	94
Net charge-offs	(128)	(86)
Allowance for loan losses, ending balance	553	539
Allowance for loan commitments, ending balance
Total ending allowance for credit losses	$ 553	$ 539