Loans and Allowance for Credit Losses (Allowance for Credit Losses on Financing Receivables) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Allowance for credit losses:
Beginning balance	$ 8,726	$ 8,316
Charge-offs	(317)	(570)
Recoveries	91	113
Net charge-offs	(226)	(457)
Provision	427	450
Ending balance	8,927	8,309
Commercial and Residential Real Estate Portfolio Segment [Member] | Construction Loans [Member]
Allowance for credit losses:
Beginning balance	2,787	1,646
Charge-offs	(29)	(241)
Recoveries	7	6
Net charge-offs	(22)	(235)
Provision	(475)	342
Ending balance	2,290	1,753
Residential Portfolio Segment [Member]
Allowance for credit losses:
Beginning balance	1,953	2,181
Charge-offs	(223)	(16)
Recoveries	11	34
Net charge-offs	(212)	18
Provision	390	(185)
Ending balance	2,131	2,014
Commercial Real Estate Portfolio Segment [Member]
Allowance for credit losses:
Beginning balance	2,610	2,999
Charge-offs		(238)
Recoveries	11
Net charge-offs	11	(238)
Provision	291	496
Ending balance	2,912	3,257
Commercial Portfolio Segment [Member]
Allowance for credit losses:
Beginning balance	1,145	558
Charge-offs	(65)	(67)
Recoveries	58	65
Net charge-offs	(7)	(2)
Provision	200	29
Ending balance	1,338	585
Consumer Portfolio Segment [Member]
Allowance for credit losses:
Beginning balance	231	156
Charge-offs		(8)
Recoveries	4	8
Net charge-offs	4
Provision	21	21
Ending balance	$ 256	177
Unallocated Financing Receivables [Member]
Allowance for credit losses:
Beginning balance		776
Provision		(253)
Ending balance		$ 523