Loans and The Allowance for Loan Losses - Summary of Past Due and Non-accrual loans, by class (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	$ 4,245	$ 8,190
Loans on Non-accrual	9,670	11,523
30-59 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	1,477	997
60-89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	516	368
Past Due 90 Days or More
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	2,252	6,825
Consumer, Excluding Consumer Other Portfolio Segment | 1-4 Family Residential
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	2,270	2,913
Loans on Non-accrual	5,549	5,190
Consumer, Excluding Consumer Other Portfolio Segment | Home Equity
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	1,822	1,178
Loans on Non-accrual	1,327	1,387
Consumer, Excluding Consumer Other Portfolio Segment | Commercial Real Estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	0	3,893
Loans on Non-accrual	2,397	4,744
Consumer, Excluding Consumer Other Portfolio Segment | 30-59 Days Past Due | 1-4 Family Residential
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	658	381
Consumer, Excluding Consumer Other Portfolio Segment | 30-59 Days Past Due | Home Equity
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	692	509
Consumer, Excluding Consumer Other Portfolio Segment | 30-59 Days Past Due | Commercial Real Estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	0	0
Consumer, Excluding Consumer Other Portfolio Segment | 60-89 Days Past Due | 1-4 Family Residential
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	275	348
Consumer, Excluding Consumer Other Portfolio Segment | 60-89 Days Past Due | Home Equity
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	222	13
Consumer, Excluding Consumer Other Portfolio Segment | 60-89 Days Past Due | Commercial Real Estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	0	0
Consumer, Excluding Consumer Other Portfolio Segment | Past Due 90 Days or More | 1-4 Family Residential
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	1,337	2,184
Consumer, Excluding Consumer Other Portfolio Segment | Past Due 90 Days or More | Home Equity
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	908	656
Consumer, Excluding Consumer Other Portfolio Segment | Past Due 90 Days or More | Commercial Real Estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	0	3,893
Commercial business
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	0
Loans on Non-accrual	305
Commercial business | 30-59 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	0
Commercial business | 60-89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	0
Commercial business | Past Due 90 Days or More
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	0
Consumer
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	153	206
Loans on Non-accrual	92	202
Consumer | 30-59 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	127	107
Consumer | 60-89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	19	7
Consumer | Past Due 90 Days or More
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	$ 7	$ 92