Loans and Allowance for Credit Losses (Rollforward of TDRs) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Financing Receivable, Allowance for Credit Losses [Line Items]
TDR beginning balance	$ 18,504	$ 20,923
New TDRs		2,570
Disbursements (payments)	(341)	(1,604)
Charge offs	(89)	(358)
TDR ending balance	18,074	21,531
TDR, related allowance	1,049	1,458
Impaired Nonaccrual Loans [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
TDR beginning balance	5,504	5,428
New TDRs		2,570
Disbursements (payments)	(212)	(979)
Charge offs		(241)
TDR ending balance	5,292	6,778
TDR, related allowance	800	766
Impaired Nonaccrual Loans [Member] | Residential Portfolio Segment [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
TDR beginning balance	1,603	445
Disbursements (payments)	(22)	(288)
TDR ending balance	1,581	157
TDR, related allowance	134	11
Impaired Nonaccrual Loans [Member] | Commercial Real Estate Portfolio Segment [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
TDR beginning balance	83
TDR ending balance	83
Impaired Nonaccrual Loans [Member] | Consumer Portfolio Segment [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
TDR beginning balance		23
TDR ending balance		23
Impaired Nonaccrual Loans [Member] | Construction Loans [Member] | Commercial and Residential Real Estate Portfolio Segment [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
TDR beginning balance	3,818	4,960
New TDRs		2,570
Disbursements (payments)	(190)	(691)
Charge offs		(241)
TDR ending balance	3,628	6,598
TDR, related allowance	666	755
Impaired Accruing Restructured Loans [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
TDR beginning balance	13,000	15,495
Disbursements (payments)	(129)	(625)
Charge offs	(89)	(117)
TDR ending balance	12,782	14,753
TDR, related allowance	249	692
Impaired Accruing Restructured Loans [Member] | Residential Portfolio Segment [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
TDR beginning balance	3,875	5,686
Disbursements (payments)	(82)	(31)
Charge offs	(89)
TDR ending balance	3,704	5,655
TDR, related allowance	148	112
Impaired Accruing Restructured Loans [Member] | Commercial Real Estate Portfolio Segment [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
TDR beginning balance	4,936	5,740
Disbursements (payments)	(37)	(517)
Charge offs		(117)
TDR ending balance	4,899	5,106
TDR, related allowance	84	552
Impaired Accruing Restructured Loans [Member] | Construction Loans [Member] | Commercial and Residential Real Estate Portfolio Segment [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
TDR beginning balance	4,189	4,069
Disbursements (payments)	(10)	(77)
TDR ending balance	4,179	3,992
TDR, related allowance	$ 17	$ 28