Loans and Allowance for Credit Losses on Loans - Credit Quality Indicators (Details) - USD ($)	Dec. 31, 2020	Jan. 01, 2020	Dec. 31, 2019
Loans
2020	$ 979,432,000
2019	309,922,000
2018	191,961,000
2017	202,725,000
2016	163,654,000
2015 and Prior	326,918,000
Revolving	451,375,000
Total loan balance	2,625,987,000	$ 31,855,000	$ 2,534,163,000
Balance to report	2,574,861,000		2,510,559,000
Loan classified as loss
Loans
Balance to report	0		0
Commercial
Loans
2020	453,231,000
2019	34,122,000
2018	22,510,000
2017	15,551,000
2016	10,565,000
2015 and Prior	8,561,000
Revolving	301,846,000
Total loan balance	846,386,000	6,790,000	603,345,000
Commercial | Pass [Member]
Loans
2020	431,369,000
2019	33,350,000
2018	21,154,000
2017	13,840,000
2016	7,341,000
2015 and Prior	8,292,000
Revolving	296,286,000
Total loan balance	811,632,000
Commercial | Special Mention [Member]
Loans
2020	15,720,000
2019	716,000
2018	1,301,000
2017	953,000
2016	713,000
2015 and Prior	170,000
Revolving	1,937,000
Total loan balance	21,510,000
Commercial | Substandard [Member]
Loans
2020	4,036,000
2018	19,000
2017	758,000
2016	2,396,000
2015 and Prior	73,000
Revolving	3,236,000
Total loan balance	10,518,000
Commercial | Substandard-Nonaccrual [Member]
Loans
2020	2,106,000
2019	56,000
2018	36,000
2016	115,000
2015 and Prior	26,000
Revolving	387,000
Total loan balance	2,726,000
CRE - owner occupied
Loans
2020	177,614,000
2019	75,632,000
2018	72,596,000
2017	55,442,000
2016	50,716,000
2015 and Prior	112,398,000
Revolving	15,964,000
Total loan balance	560,362,000	6,994,000	548,907,000
CRE - owner occupied | Pass [Member]
Loans
2020	168,224,000
2019	73,064,000
2018	68,068,000
2017	51,705,000
2016	50,716,000
2015 and Prior	109,350,000
Revolving	15,964,000
Total loan balance	537,091,000
CRE - owner occupied | Special Mention [Member]
Loans
2020	3,151,000
2019	2,568,000
2018	4,128,000
2017	783,000
2015 and Prior	2,569,000
Total loan balance	13,199,000
CRE - owner occupied | Substandard [Member]
Loans
2020	2,561,000
2018	400,000
2017	2,954,000
2015 and Prior	451,000
Total loan balance	6,366,000
CRE - owner occupied | Substandard-Nonaccrual [Member]
Loans
2020	3,678,000
2015 and Prior	28,000
Total loan balance	3,706,000
CRE - non-owner occupied
Loans
2020	181,646,000
2019	128,361,000
2018	72,764,000
2017	99,816,000
2016	57,907,000
2015 and Prior	150,683,000
Revolving	1,926,000
Total loan balance	693,103,000	11,672,000	767,821,000
CRE - non-owner occupied | Pass [Member]
Loans
2020	166,550,000
2019	128,361,000
2018	68,796,000
2017	99,816,000
2016	57,422,000
2015 and Prior	150,683,000
Revolving	1,926,000
Total loan balance	673,554,000
CRE - non-owner occupied | Special Mention [Member]
Loans
2020	11,930,000
2018	2,557,000
Total loan balance	14,487,000
CRE - non-owner occupied | Substandard [Member]
Loans
2020	3,166,000
2018	1,411,000
2016	485,000
Total loan balance	5,062,000
Land and construction
Loans
2020	116,291,000
2019	22,054,000
2015 and Prior	1,343,000
Revolving	4,906,000
Total loan balance	144,594,000	1,458,000	147,189,000
Land and construction | Pass [Member]
Loans
2020	114,932,000
2019	22,054,000
2015 and Prior	1,343,000
Revolving	4,906,000
Total loan balance	143,235,000
Land and construction | Substandard [Member]
Loans
2020	1,359,000
Total loan balance	1,359,000
Home equity
Loans
2020	383,000
2018	74,000
2015 and Prior	143,000
Revolving	111,285,000
Total loan balance	111,885,000	1,321,000	151,775,000
Home equity | Pass [Member]
Loans
2020	266,000
2018	74,000
Revolving	109,848,000
Total loan balance	110,188,000
Home equity | Substandard [Member]
Loans
2015 and Prior	143,000
Revolving	605,000
Total loan balance	748,000
Home equity | Substandard-Nonaccrual [Member]
Loans
2020	117,000
Revolving	832,000
Total loan balance	949,000
Multi-family
Loans
2020	32,370,000
2019	39,183,000
2018	17,248,000
2017	24,572,000
2016	16,235,000
2015 and Prior	35,937,000
Revolving	880,000
Total loan balance	166,425,000	1,253,000	180,623,000
Multi-family | Pass [Member]
Loans
2020	31,481,000
2019	39,183,000
2018	17,248,000
2017	24,572,000
2016	16,235,000
2015 and Prior	30,751,000
Revolving	880,000
Total loan balance	160,350,000
Multi-family | Special Mention [Member]
Loans
2015 and Prior	5,186,000
Total loan balance	5,186,000
Multi-family | Substandard [Member]
Loans
2020	889,000
Total loan balance	889,000
Residential mortgages
Loans
2020	17,887,000
2019	10,048,000
2018	4,876,000
2017	7,324,000
2016	28,115,000
2015 and Prior	16,866,000
Total loan balance	85,116,000	678,000	100,759,000
Residential mortgages | Pass [Member]
Loans
2020	12,798,000
2019	10,048,000
2018	3,246,000
2017	7,324,000
2016	28,115,000
2015 and Prior	15,568,000
Total loan balance	77,099,000
Residential mortgages | Special Mention [Member]
Loans
2020	5,089,000
2018	1,630,000
Total loan balance	6,719,000
Residential mortgages | Substandard [Member]
Loans
2015 and Prior	1,298,000
Total loan balance	1,298,000
Consumer and other
Loans
2020	10,000
2019	522,000
2018	1,893,000
2017	20,000
2016	116,000
2015 and Prior	987,000
Revolving	14,568,000
Total loan balance	18,116,000	$ 1,689,000	$ 33,744,000
Consumer and other | Pass [Member]
Loans
2020	10,000
2019	522,000
2018	1,486,000
2017	20,000
2016	116,000
2015 and Prior	987,000
Revolving	14,568,000
Total loan balance	17,709,000
Consumer and other | Substandard-Nonaccrual [Member]
Loans
2018	407,000
Total loan balance	407,000
Risk Grades [Member]
Loans
2020	979,432,000
2019	309,922,000
2018	191,961,000
2017	202,725,000
2016	163,654,000
2015 and Prior	326,918,000
Revolving	451,375,000
Total loan balance	2,625,987,000
Risk Grades [Member] | Pass [Member]
Loans
2020	925,630,000
2019	306,582,000
2018	180,072,000
2017	197,277,000
2016	159,945,000
2015 and Prior	316,974,000
Revolving	444,378,000
Total loan balance	2,530,858,000
Risk Grades [Member] | Special Mention [Member]
Loans
2020	35,890,000
2019	3,284,000
2018	9,616,000
2017	1,736,000
2016	713,000
2015 and Prior	7,925,000
Revolving	1,937,000
Total loan balance	61,101,000
Risk Grades [Member] | Substandard [Member]
Loans
2020	12,011,000
2018	1,830,000
2017	3,712,000
2016	2,881,000
2015 and Prior	1,965,000
Revolving	3,841,000
Total loan balance	26,240,000
Risk Grades [Member] | Substandard-Nonaccrual [Member]
Loans
2020	5,901,000
2019	56,000
2018	443,000
2016	115,000
2015 and Prior	54,000
Revolving	1,219,000
Total loan balance	$ 7,788,000