Allowance for Loan Losses - Recorded Investment in Consumer Loan Classes by Performing and Nonperforming Status (Details) - Consumer - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Financing Receivable, Recorded Investment [Line Items]
Loans and leases receivable, gross	$ 1,256,024	$ 1,190,735
% of Total	100.00%	100.00%
Performing
Financing Receivable, Recorded Investment [Line Items]
Loans and leases receivable, gross	$ 1,242,559	$ 1,182,104
% of Total	98.90%	99.30%
Nonperforming
Financing Receivable, Recorded Investment [Line Items]
Loans and leases receivable, gross	$ 13,465	$ 8,631
% of Total	1.10%	0.70%
Residential Mortgage
Financing Receivable, Recorded Investment [Line Items]
Loans and leases receivable, gross	$ 701,982	$ 639,372
% of Total	100.00%	100.00%
Residential Mortgage | Performing
Financing Receivable, Recorded Investment [Line Items]
Loans and leases receivable, gross	$ 692,064	$ 633,743
% of Total	98.60%	99.10%
Residential Mortgage | Nonperforming
Financing Receivable, Recorded Investment [Line Items]
Loans and leases receivable, gross	$ 9,918	$ 5,629
% of Total	1.40%	0.90%
Home Equity
Financing Receivable, Recorded Investment [Line Items]
Loans and leases receivable, gross	$ 482,284	$ 470,845
% of Total	100.00%	100.00%
Home Equity | Performing
Financing Receivable, Recorded Investment [Line Items]
Loans and leases receivable, gross	$ 478,845	$ 467,943
% of Total	99.30%	99.40%
Home Equity | Nonperforming
Financing Receivable, Recorded Investment [Line Items]
Loans and leases receivable, gross	$ 3,439	$ 2,902
% of Total	0.70%	0.60%
Installment and Other Consumer
Financing Receivable, Recorded Investment [Line Items]
Loans and leases receivable, gross	$ 65,852	$ 73,939
% of Total	100.00%	100.00%
Installment and Other Consumer | Performing
Financing Receivable, Recorded Investment [Line Items]
Loans and leases receivable, gross	$ 65,744	$ 73,839
% of Total	99.80%	99.80%
Installment and Other Consumer | Nonperforming
Financing Receivable, Recorded Investment [Line Items]
Loans and leases receivable, gross	$ 108	$ 100
% of Total	0.20%	0.20%
Consumer Construction
Financing Receivable, Recorded Investment [Line Items]
Loans and leases receivable, gross	$ 5,906	$ 6,579
% of Total	100.00%	100.00%
Consumer Construction | Performing
Financing Receivable, Recorded Investment [Line Items]
Loans and leases receivable, gross	$ 5,906	$ 6,579
% of Total	100.00%	100.00%
Consumer Construction | Nonperforming
Financing Receivable, Recorded Investment [Line Items]
Loans and leases receivable, gross	$ 0	$ 0
% of Total	0.00%	0.00%