Allowance for Loan Losses - Activity by Class (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	$ 16,253	$ 11,639	$ 11,639
Charge offs	279	255	1,661
Recoveries	95	74	225
Provision (credit)	525	400	6,050
Ending balance	16,594	11,858	16,253
Ending balance specifically evaluated for impairment	900	992	462
Ending balance collectively evaluated for impairment	15,694	10,866	15,791
Ending balance	1,516,772	1,344,208	1,476,761
Ending balance specifically evaluated for impairment	16,340	22,493	16,039
Ending balance collectively evaluated for impairment	1,500,432	1,321,715	1,460,722
Commercial \| Real estate
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	5,178	3,742	3,742
Charge offs	5	0	1,088
Recoveries	65	0	0
Provision (credit)	503	120	2,524
Ending balance	5,741	3,862	5,178
Ending balance specifically evaluated for impairment	174	230	112
Ending balance collectively evaluated for impairment	5,567	3,632	5,066
Ending balance	469,974	382,753	442,121
Ending balance specifically evaluated for impairment	3,201	6,223	3,029
Ending balance collectively evaluated for impairment	466,773	376,530	439,092
Commercial \| Construction
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	662	365	365
Charge offs	0	0	0
Recoveries	0	0	0
Provision (credit)	(13)	59	297
Ending balance	649	424	662
Ending balance specifically evaluated for impairment	21	3	18
Ending balance collectively evaluated for impairment	628	421	644
Ending balance	53,394	43,913	56,565
Ending balance specifically evaluated for impairment	770	947	770
Ending balance collectively evaluated for impairment	52,624	42,966	55,795
Commercial \| Other
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	3,438	3,329	3,329
Charge offs	142	0	27
Recoveries	0	20	37
Provision (credit)	784	(922)	99
Ending balance	4,080	2,427	3,438
Ending balance specifically evaluated for impairment	563	172	169
Ending balance collectively evaluated for impairment	3,517	2,255	3,269
Ending balance	297,488	237,896	285,015
Ending balance specifically evaluated for impairment	2,220	990	1,779
Ending balance collectively evaluated for impairment	295,268	236,906	283,236
Municipal
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	171	27	27
Charge offs	0	0	0
Recoveries	0	0	0
Provision (credit)	14	2	144
Ending balance	185	29	171
Ending balance specifically evaluated for impairment	0	0	0
Ending balance collectively evaluated for impairment	185	29	171
Ending balance	49,476	43,537	43,783
Ending balance specifically evaluated for impairment	0	0	0
Ending balance collectively evaluated for impairment	49,476	43,537	43,783
Residential \| Construction
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	102	25	25
Charge offs	0	0	0
Recoveries	0	0	0
Provision (credit)	29	7	77
Ending balance	131	32	102
Ending balance specifically evaluated for impairment	0	0	0
Ending balance collectively evaluated for impairment	131	32	102
Ending balance	24,796	15,202	21,600
Ending balance specifically evaluated for impairment	0	0	0
Ending balance collectively evaluated for impairment	24,796	15,202	21,600
Residential \| Term
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	2,579	1,024	1,024
Charge offs	29	2	66
Recoveries	6	10	34
Provision (credit)	406	194	1,587
Ending balance	2,962	1,226	2,579
Ending balance specifically evaluated for impairment	142	233	163
Ending balance collectively evaluated for impairment	2,820	993	2,416
Ending balance	520,317	500,971	522,070
Ending balance specifically evaluated for impairment	9,267	12,038	9,414
Ending balance collectively evaluated for impairment	511,050	488,933	512,656
Home equity line of credit
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	1,211	1,078	1,078
Charge offs	0	153	153
Recoveries	1	1	22
Provision (credit)	(265)	86	264
Ending balance	947	1,012	1,211
Ending balance specifically evaluated for impairment	0	296	0
Ending balance collectively evaluated for impairment	947	716	1,211
Ending balance	77,210	90,674	79,750
Ending balance specifically evaluated for impairment	875	2,228	1,039
Ending balance collectively evaluated for impairment	76,335	88,446	78,711
Consumer
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	778	867	867
Charge offs	103	100	327
Recoveries	23	43	132
Provision (credit)	174	(85)	106
Ending balance	872	725	778
Ending balance specifically evaluated for impairment	0	58	0
Ending balance collectively evaluated for impairment	872	667	778
Ending balance	24,117	29,262	25,857
Ending balance specifically evaluated for impairment	7	67	8
Ending balance collectively evaluated for impairment	24,110	29,195	25,849
Unallocated
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	2,134	1,182	1,182
Charge offs	0	0	0
Recoveries	0	0	0
Provision (credit)	(1,107)	939	952
Ending balance	1,027	2,121	2,134
Ending balance specifically evaluated for impairment	0	0	0
Ending balance collectively evaluated for impairment	1,027	2,121	2,134
Ending balance	0	0	0
Ending balance specifically evaluated for impairment	0	0	0
Ending balance collectively evaluated for impairment	$ 0	$ 0	$ 0

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

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- Definition

A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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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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- Definition

Amount of allowance for credit loss on financing receivable. Excludes allowance for financing receivable covered under loss sharing agreement.

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- Definition

The valuation allowance for financing receivables that are expected to be uncollectible that were collectively evaluated for impairment.

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Amount of valuation allowance for financing receivables that are expected to be uncollectible that were individually evaluated for impairment.

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The balance of financing receivables that were collectively evaluated for impairment.

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Amount, before allowance for credit loss, of financing receivable.

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Amount of expense related to estimated loss from loan and lease transactions.

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