Loans, Allowance for Loan Losses and Credit Quality - Summary of Average Recorded Investment and Interest Income recognized on Impaired Loans (Details) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019
Financing Receivable Impaired [Line Items]
Impaired loans, Average recorded investment	$ 3,919	$ 5,102
Impaired loans, Ending recorded investment	4,069	5,423	$ 3,769
Impaired loans, Interest income	37	47
Home Equity Lines of Credit
Financing Receivable Impaired [Line Items]
Impaired loans, Average recorded investment	314	212
Impaired loans, Ending recorded investment	314	325	314
Impaired loans, Interest income	1	2
Commercial Loans
Financing Receivable Impaired [Line Items]
Impaired loans, Average recorded investment	410	344
Impaired loans, Ending recorded investment	407	427	412
Impaired loans, Interest income	4	5
Consumer Loans
Financing Receivable Impaired [Line Items]
Impaired loans, Average recorded investment		171
Impaired loans, Ending recorded investment		51
Impaired loans, Interest income		2
Mortgage Loans on Real Estate
Financing Receivable Impaired [Line Items]
Impaired loans, Average recorded investment	3,195	4,375
Impaired loans, Ending recorded investment	3,348	4,620	3,043
Impaired loans, Interest income	32	38
Mortgage Loans on Real Estate \| Residential Real Estate
Financing Receivable Impaired [Line Items]
Impaired loans, Average recorded investment	667	2,007
Impaired loans, Ending recorded investment	741	2,007	593
Impaired loans, Interest income	5	6
Mortgage Loans on Real Estate \| Commercial Real Estate
Financing Receivable Impaired [Line Items]
Impaired loans, Average recorded investment	2,384	2,212
Impaired loans, Ending recorded investment	2,464	2,458	2,304
Impaired loans, Interest income	25	30
Mortgage Loans on Real Estate \| Construction and Land Development
Financing Receivable Impaired [Line Items]
Impaired loans, Average recorded investment	144	156
Impaired loans, Ending recorded investment	143	155	$ 146
Impaired loans, Interest income	$ 2	$ 2

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Average amount of investment of impaired financing receivables with related allowance for credit losses and without a related allowance for credit losses.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 15
-Subparagraph (c)(1)
-URI http://asc.fasb.org/extlink&oid=118936363&loc=d3e5212-111524

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 17
-URI http://asc.fasb.org/extlink&oid=118936363&loc=d3e5258-111524

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Amount of interest income recognized that the financing receivables (with related allowance for credit losses and without a related allowance for credit losses) were impaired.

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+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 14A
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=118936363&loc=SL6953550-111524

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