Loans and the Allowance for Loan Losses - Summary of Changes in Allowance for Loan Losses Disaggregated by Loan Type (Details) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2019	Mar. 31, 2018
Financing Receivable Allowance For Credit Losses [Line Items]
Allowance for loan losses, Beginning balance	$ 16,768	$ 15,320
Charge-offs	(39)	(10)
Recoveries	16	13
Provision for (Release of)	(93)	409
Allowance for loan losses, Ending balance	16,652	15,732
Residential Mortgage
Financing Receivable Allowance For Credit Losses [Line Items]
Allowance for loan losses, Beginning balance	4,946	5,047
Provision for (Release of)	310	(355)
Allowance for loan losses, Ending balance	5,256	4,692
Commercial Mortgage
Financing Receivable Allowance For Credit Losses [Line Items]
Allowance for loan losses, Beginning balance	9,626	8,289
Provision for (Release of)	(257)	648
Allowance for loan losses, Ending balance	9,369	8,937
Home Equity
Financing Receivable Allowance For Credit Losses [Line Items]
Allowance for loan losses, Beginning balance	517	630
Provision for (Release of)	17	(60)
Allowance for loan losses, Ending balance	534	570
Commercial & Industrial
Financing Receivable Allowance For Credit Losses [Line Items]
Allowance for loan losses, Beginning balance	1,415	946
Charge-offs	(30)	(5)
Recoveries	12	11
Provision for (Release of)	(152)	193
Allowance for loan losses, Ending balance	1,245	1,145
Consumer
Financing Receivable Allowance For Credit Losses [Line Items]
Allowance for loan losses, Beginning balance	264	315
Charge-offs	(9)	(5)
Recoveries	4	2
Provision for (Release of)	(11)	(14)
Allowance for loan losses, Ending balance	$ 248	298
Impaired
Financing Receivable Allowance For Credit Losses [Line Items]
Allowance for loan losses, Beginning balance		93
Provision for (Release of)		(3)
Allowance for loan losses, Ending balance		$ 90

Amount of recovery of loans and lease receivables which had previously been fully or partially written-off as bad debts.

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Amount of increase (decrease) of allowance reserve for credit loss.

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Amount of loans and leases that have been written off from both loan receivables and allowance reserve for credit loss.

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Amount of allowance to cover probable credit losses on loans and leases. Includes carryover of or adjustments to the allowance for loan losses in connection with business combinations. Excludes allowance for loans and leases covered under loss sharing agreements.

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