Loans (Narrative) (Details)	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2020 USD ($) Customer numberOfLoans numberOfLoanCategories	Jun. 30, 2019 USD ($)	Jun. 30, 2020 USD ($) Customer numberOfTDRLoans loan numberOfLoans numberOfLoanCategories	Jun. 30, 2019 USD ($)	Dec. 31, 2019 USD ($) loan numberOfTDRLoans numberOfLoans Customer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of loan categories | numberOfLoanCategories	2		2
Unamortized Loan Commitment and Origination Fees and Unamortized Discounts or Premiums	$ 2,100,000		$ 2,100,000		$ 1,900,000
Deferred loan fees and premiums include net deferred fees paid by customers	3,200,000		3,200,000		3,300,000
Offset by net deferred premiums paid to purchase loans	$ 5,300,000		$ 5,300,000		$ 5,200,000
Number of customer relationships | Customer	10		10		7
Loans receivable	$ 1,622,129,000		$ 1,622,129,000		$ 1,454,172,000
Service rights retained, percent of outstanding balance	0.25%		0.25%
Service rights retained, amount	$ 29,100,000		$ 29,100,000		$ 32,900,000
Total number of loans | numberOfLoans	39		39		39
Non- accrual delinquent loans	$ 20,077,000		$ 20,077,000		$ 12,787,000
Reserve for delinquent non accrual loans	100,000		100,000		522,000
Non-accrual loans included in TDR's	22,896,000		$ 22,896,000		$ 17,857,000
Number of TDR loans | numberOfTDRLoans			8		8
Financing receivable post modification recorded investment	2,189,000		$ 2,189,000		$ 2,049,000
Loans added to troubled debt restructuring | numberOfLoans			1		1
Amount of loans added to TDR			$ 194,000		$ 25,000
Allowance for loan loss	$ 16,319,000		$ 16,319,000		$ 10,942,000
Loans and leases receivable, allowance percentage	1.09%		1.09%		0.75%
Unpaid Contractual Principal Balance	$ 26,729,000	$ 27,515,000	$ 26,729,000	$ 27,515,000	$ 28,235,000
Total Recorded Investment	26,500,000	27,458,000	26,500,000	27,458,000	27,986,000
PCI Loans, accretion interest	181,000	209,000
Reclassification from (to) nonaccretable difference	24,000	156,000	24,000	156,000
Portfolio Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unamortized Loan Commitment and Origination Fees and Unamortized Discounts or Premiums	$ 2,072,000		$ 2,072,000		$ 1,879,000
Percentage status of loan in portfolio	100.00%		100.00%		100.00%
Loans receivable	$ 1,492,745,000	1,387,186,000	$ 1,492,745,000	1,387,186,000	$ 1,454,172,000
Allowance for loan loss	$ (16,319,000)		$ (16,319,000)		$ (10,942,000)
Loans and leases receivable, allowance percentage	1.09%		1.09%		0.75%
Adjustable Rate Residential First Mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable	$ 1,500,000,000		$ 1,500,000,000
Twelve Loans And Four Customer Relationships
Accounts, Notes, Loans and Financing Receivable [Line Items]
Increase (decrease) in finance receivables			$ 20,000,000.0		$ 15,000,000.0
Total number of loans | numberOfLoans	21		21		18
Percentage status of non accrual loans			87.00%		84.00%
Financing Receivable Troubled Debt Restructuring
Accounts, Notes, Loans and Financing Receivable [Line Items]
Increase (decrease) in finance receivables			$ 140,000
TDR loan principal curtailment					$ 236,000
One Troubled Debt Restructuring Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non-accrual loans included in TDR's	$ 1,600,000		$ 1,600,000		$ 1,400,000
Number of TDR loans | loan			4
Financing receivable post modification recorded investment	60,000		$ 60,000
Seven Troubled Debt Restructuring Loans with Reserves
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of TDR loans | loan					3
Specific reserves for TDR loans					$ 87,000
Financing receivable post modification recorded investment					$ 88,000
Seven Trouble Debt Restructuring Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans removed from troubled debt restructuring | loan			1		7
Amount of loans removed from troubled debt restructuring			$ 29,000		$ 4,400,000
U.S. SBA PPP Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unamortized Loan Commitment and Origination Fees and Unamortized Discounts or Premiums	(3,700,000)		(3,700,000)
Offset by net deferred premiums paid to purchase loans	733,000		733,000
Loans receivable	$ 129,400,000		$ 129,400,000
Total number of loans | numberOfLoans	902		902
Debt Instrument, Interest Rate, Stated Percentage	1.00%		1.00%
Deferred loan fees and premiums included in deferred fees paid by SBA	$ 4,500,000		$ 4,500,000
Loans with minimum financing term	$ 129,000,000.0		$ 129,000,000.0
Loans with minimum financing term, percent of total	99.74%		99.74%
Trouble Debt Restructuring Loans Disposal
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amount of loans removed from troubled debt restructuring			$ 25,000
Federal Reserve PPPLF Program Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable	$ 126,800,000		$ 126,800,000
Nonaccrual Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Percentage status of loan in portfolio	1.41%		1.41%		1.23%
Increase (decrease) in finance receivables			$ 5,000,000.0
Total number of loans | numberOfLoans	39		39		39
Non- accrual delinquent loans	$ 22,900,000		$ 22,900,000		$ 17,900,000
Decrease in loan delinquency					(1,400,000)
Nonaccrual Loans With No Impairment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non- accrual delinquent loans	2,800,000		$ 2,800,000		$ 5,100,000
Percentage of current loans on total non accrual loans			12.00%		28.00%
Non-accrual loans included in TDR's	22,100,000		$ 22,100,000		$ 11,700,000
Interest due to debt			689,000		318,000
Nonaccrual Loans With Impairment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non- accrual delinquent loans	20,100,000		$ 20,100,000		$ 12,800,000
Percentage of delinquent loans on total non accrual loans			88.00%		72.00%
Non-accrual loans included in TDR's	870,000		$ 870,000		$ 6,100,000
Interest due to debt			105,000		302,000
Minimum | Commercial loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Bank exposure, threshold limit for credit rating			$ 1,000,000
Minimum | U.S. SBA PPP Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Debt Instrument, Term			2 years
Maximum | U.S. SBA PPP Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Debt Instrument, Term			5 years
Unrated
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable	538,940,000		$ 538,940,000		350,699,000
Pass
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable	1,060,743,000		1,060,743,000		1,076,610,000
Substandard
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable	21,420,000		$ 21,420,000		26,863,000
Residential rentals | Minimum
Accounts, Notes, Loans and Financing Receivable [Line Items]
Debt maturity period			3 years
Residential rentals | Maximum
Accounts, Notes, Loans and Financing Receivable [Line Items]
Debt maturity period			20 years
Commercial real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Largest commercial real estate loan outstanding	21,000,000.0		$ 21,000,000.0		21,100,000
Loans receivable	$ 996,111,000		$ 996,111,000		$ 964,777,000
Total number of loans | numberOfLoans	23		23		16
Non- accrual delinquent loans	$ 18,083,000		$ 18,083,000		$ 10,562,000
Non-accrual loans included in TDR's	19,961,000		$ 19,961,000		$ 12,249,000
Number of TDR loans | numberOfTDRLoans			3		3
Financing receivable post modification recorded investment	1,408,000		$ 1,408,000		$ 1,420,000
Unpaid Contractual Principal Balance	21,360,000	20,933,000	21,360,000	20,933,000	20,914,000
Total Recorded Investment	$ 21,157,000	20,918,000	$ 21,157,000	20,918,000	$ 20,707,000
Commercial real estate | Portfolio Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Percentage status of loan in portfolio	66.73%		66.73%		66.34%
Loans receivable	$ 996,111,000	917,948,000	$ 996,111,000	917,948,000	$ 964,777,000
Commercial real estate | Unrated
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable	150,661,000		150,661,000		102,695,000
Commercial real estate | Pass
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable	826,315,000		826,315,000		840,403,000
Commercial real estate | Substandard
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable	$ 18,938,000		$ 18,938,000		$ 21,679,000
Commercial real estate | Commercial Construction Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Percentage status of loan in portfolio	10.20%		10.20%		8.90%
Percent of appraised value or sales price			80.00%
Residential first mortgages
Accounts, Notes, Loans and Financing Receivable [Line Items]
Increase (decrease) in finance receivables			$ 21,900,000		$ 41,000,000.0
Loans receivable	$ 165,670,000		$ 165,670,000		$ 167,710,000
Total number of loans | numberOfLoans	1		1		3
Non-accrual loans included in TDR's	$ 194,000		$ 194,000		$ 830,000
Number of TDR loans | numberOfTDRLoans			2		1
Financing receivable post modification recorded investment	257,000		$ 257,000		$ 64,000
ALLL increased			5,400,000
Allowance for loan loss	$ 16,300,000		$ 16,300,000		10,900,000
Loans and leases receivable, allowance percentage	(49.14%)		(49.14%)
Unpaid Contractual Principal Balance	$ 1,710,000	2,124,000	$ 1,710,000	2,124,000	1,921,000
Total Recorded Investment	$ 1,710,000	2,123,000	$ 1,710,000	2,123,000	$ 1,917,000
Residential first mortgages | Portfolio Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Percentage status of loan in portfolio	11.10%		11.10%		11.53%
Loans receivable	$ 165,670,000	156,670,000	$ 165,670,000	156,670,000	$ 167,710,000
Residential first mortgages | Adjustable Rate Residential First Mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Percentage status of loan in portfolio	2.90%		2.90%		3.60%
Loans receivable	$ 43,200,000		$ 43,200,000		$ 52,300,000
Residential first mortgages | Minimum
Accounts, Notes, Loans and Financing Receivable [Line Items]
Debt maturity period			10 years
Residential first mortgages | Maximum
Accounts, Notes, Loans and Financing Receivable [Line Items]
Debt maturity period			30 years
Residential rentals
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable	132,590,000		$ 132,590,000		$ 123,601,000
Largest residential first mortgage loans outstanding, amount	3,000,000.0		3,000,000.0
Largest residential rental mortgage loan outstanding, amount	$ 9,700,000		$ 9,700,000
Number of properties secured as collateral | numberOfLoans	120		120
Total number of loans | numberOfLoans	2		2		5
Non-accrual loans included in TDR's	$ 281,000		$ 281,000		$ 937,000
Unpaid Contractual Principal Balance	643,000	971,000	643,000	971,000	941,000
Total Recorded Investment	$ 643,000	971,000	$ 643,000	971,000	$ 937,000
Residential rentals | Portfolio Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Percentage status of loan in portfolio	8.88%		8.88%		8.50%
Loans receivable	$ 132,590,000	121,990,000	$ 132,590,000	121,990,000	$ 123,601,000
Residential rentals | 1-4 Family Units
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable	103,300,000		103,300,000		97,100,000
Residential rentals | Apartment Buildings Rentals
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable	$ 29,300,000		$ 29,300,000		$ 26,500,000
Percent of appraised value or sales price			80.00%
Residential rentals | Adjustable Rate Residential Rentals
Accounts, Notes, Loans and Financing Receivable [Line Items]
Percentage status of loan in portfolio	7.50%		7.50%		7.00%
Loans receivable	$ 112,400,000		$ 112,400,000		$ 102,200,000
Residential rentals | Minimum
Accounts, Notes, Loans and Financing Receivable [Line Items]
Debt maturity period			3 years
Residential rentals | Maximum
Accounts, Notes, Loans and Financing Receivable [Line Items]
Debt maturity period			20 years
Residential rentals | Unrated
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable	47,992,000		$ 47,992,000		38,139,000
Residential rentals | Pass
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable	84,236,000		84,236,000		84,811,000
Residential rentals | Substandard
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable	$ 0		$ 0		$ 651,000
Construction and land development
Accounts, Notes, Loans and Financing Receivable [Line Items]
Percentage status of loan in portfolio	2.50%		2.50%		2.40%
Loans receivable	$ 37,580,000		$ 37,580,000		$ 34,133,000
Largest construction and land development loan outstanding, amount	$ 7,700,000		$ 7,700,000		$ 5,300,000
Construction and land development | Portfolio Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Percentage status of loan in portfolio	2.52%		2.52%		2.35%
Loans receivable	$ 37,580,000	35,662,000	$ 37,580,000	35,662,000	$ 34,133,000
Construction and land development | Unrated
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable	1,950,000		1,950,000		2,075,000
Construction and land development | Pass
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable	$ 35,630,000		$ 35,630,000		32,058,000
Construction and land development | Substandard
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable					$ 0
Home equity and second mortgages
Accounts, Notes, Loans and Financing Receivable [Line Items]
Percentage status of loan in portfolio	2.30%		2.30%		2.50%
Loans receivable	$ 33,900,000		$ 33,900,000		$ 36,100,000
Home equity and second mortgages | Portfolio Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Percentage status of loan in portfolio	2.27%		2.27%		2.48%
Loans receivable	$ 33,873,000		$ 33,873,000		$ 36,098,000
Commercial loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Percentage status of loan in portfolio	4.20%		4.20%		4.30%
Debt maturity period			5 years
Loans receivable	$ 63,249,000		$ 63,249,000		$ 63,102,000
Largest commercial loan outstanding, amount	$ 6,700,000		$ 6,700,000		$ 2,800,000
Total number of loans | numberOfLoans	2		2		3
Non- accrual delinquent loans	$ 1,807,000		$ 1,807,000		$ 1,807,000
Non-accrual loans included in TDR's	1,807,000		1,807,000		3,127,000
Unpaid Contractual Principal Balance	1,807,000	2,638,000	1,807,000	2,638,000	3,127,000
Total Recorded Investment	$ 1,807,000	2,626,000	$ 1,807,000	2,626,000	$ 3,127,000
Commercial loans | Portfolio Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Percentage status of loan in portfolio	4.24%		4.24%		4.34%
Loans receivable	$ 63,249,000	67,617,000	$ 63,249,000	67,617,000	$ 63,102,000
Commercial loans | Unrated
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable	16,018,000		16,018,000		16,754,000
Commercial loans | Pass
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable	45,424,000		45,424,000		43,221,000
Commercial loans | Substandard
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable	1,807,000		1,807,000		3,127,000
Consumer loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable	1,117,000		1,117,000		$ 1,104,000
Non- accrual delinquent loans	5,000		5,000
Unpaid Contractual Principal Balance	5,000		5,000
Total Recorded Investment	$ 5,000		$ 5,000
Consumer loans | Portfolio Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Percentage status of loan in portfolio	0.07%		0.07%		0.08%
Loans receivable	$ 1,117,000	967,000	$ 1,117,000	967,000	$ 1,104,000
Commercial equipment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Percentage status of loan in portfolio	4.20%		4.20%		4.40%
Loans receivable	$ 62,555,000		$ 62,555,000		$ 63,647,000
Largest commercial equipment loans, amount	$ 2,000,000.0		$ 2,000,000.0		$ 2,100,000
Total number of loans | numberOfLoans	4		4		6
Non- accrual delinquent loans	$ 50,000		$ 50,000		$ 241,000
Non-accrual loans included in TDR's	65,000		$ 65,000		$ 266,000
Number of TDR loans | numberOfTDRLoans			3		4
Financing receivable post modification recorded investment	524,000		$ 524,000		$ 565,000
Unpaid Contractual Principal Balance	548,000	367,000	548,000	367,000	808,000
Total Recorded Investment	$ 533,000	349,000	$ 533,000	349,000	$ 788,000
Commercial equipment | Portfolio Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Percentage status of loan in portfolio	4.19%		4.19%		4.38%
Loans receivable	$ 62,555,000	50,466,000	$ 62,555,000	50,466,000	$ 63,647,000
Commercial equipment | Unrated
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable	26,153,000		26,153,000		26,045,000
Commercial equipment | Pass
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable	36,358,000		36,358,000		37,399,000
Commercial equipment | Substandard
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable	$ 44,000		$ 44,000		$ 203,000
Loan Delinquency
Accounts, Notes, Loans and Financing Receivable [Line Items]
Percentage status of loan in portfolio	1.74%		1.74%		0.92%
Decrease in loan delinquency					$ 12,600,000
Non-accrual loans included in TDR's	$ 25,900,000		$ 25,900,000		13,300,000
Performing Financial Instruments | Residential first mortgages
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable	165,670,000		165,670,000		167,710,000
Performing Financial Instruments | Consumer loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable	1,112,000		1,112,000		1,104,000
Nonperforming Financial Instruments | Residential first mortgages
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable	0		0		0
Nonperforming Financial Instruments | Consumer loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable	$ 5,000		$ 5,000		0
Purchased credit impaired
Accounts, Notes, Loans and Financing Receivable [Line Items]
Percentage status of loan in portfolio	0.10%		0.10%
Unpaid Contractual Principal Balance	$ 2,400,000		$ 2,400,000
Total Recorded Investment	2,000,000.0		2,000,000.0		2,400,000
Purchased credit impaired | Portfolio Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable	1,993,000	2,772,000	1,993,000	2,772,000	2,424,000
Purchased credit impaired | Commercial real estate | Portfolio Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable	1,593,000	1,725,000	1,593,000	1,725,000	1,738,000
Purchased credit impaired | Residential first mortgages | Portfolio Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable	0	451,000	0	451,000	0
Purchased credit impaired | Residential rentals | Portfolio Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable	0	327,000	0	327,000	295,000
Purchased credit impaired | Construction and land development | Portfolio Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable	$ 0	$ 0	$ 0	$ 0	$ 0
County First Acquisition
Accounts, Notes, Loans and Financing Receivable [Line Items]
Percentage status of loan in portfolio	4.14%		4.14%		5.30%
Loans receivable	$ 67,080,000		$ 67,080,000		$ 77,078,000
County First Acquisition | Purchased credit impaired
Accounts, Notes, Loans and Financing Receivable [Line Items]
Percentage status of loan in portfolio	0.12%		0.12%		0.17%
Loans receivable	$ 1,993,000		$ 1,993,000		$ 2,424,000
County First Acquisition | All Other Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Percentage status of loan in portfolio	4.01%		4.01%		5.13%
Loans receivable	$ 65,087,000		$ 65,087,000		$ 74,654,000
County First Bank Acquisition | Purchased credit impaired
Accounts, Notes, Loans and Financing Receivable [Line Items]
New acquisition accounting for fair market value adjustment	$ 414,000		$ 414,000		$ 516,000
Net acquisition accounting fair market value adjustment, mark	17.19%		17.19%		17.55%
County First Bank Acquisition | All Other Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
New acquisition accounting for fair market value adjustment	$ 889,000		$ 889,000		$ 1,200,000
Net acquisition accounting fair market value adjustment, mark	1.35%		1.35%		1.55%