Loans and Allowance for Loan Losses - TDRs and Loan Modifications (Details)	3 Months Ended		6 Months Ended
	Jun. 30, 2020 USD ($) contract loan	Jun. 30, 2019 USD ($) contract	Jun. 30, 2020 USD ($) contract loan	Jun. 30, 2019 USD ($) contract	Dec. 31, 2019 USD ($)
Troubled Debt Restructurings
Troubled debt restructurings	$ 3,800,000		$ 3,800,000		$ 4,100,000
Amount of specific reserves related to TDRs which were allocated to the allowance for loan losses	$ 353,000		$ 353,000		442,000
Number of Contracts | contract	1		2	2
Pre- Modification	$ 111,000		$ 117,000	$ 80,000
Post- Modification	119,000		124,000	80,000
Loans held for sale, at lower of cost or fair value	9,041,000	$ 121,000	9,041,000	$ 121,000	428,000
Loan Modifications under the CARES Act
Total loans held for investment	$ 1,280,615,000		$ 1,280,615,000		1,168,797,000
Percent of portfolio	22.40%		22.40%
Loan Modifications under CARES Act
Loan Modifications under the CARES Act
Loan modification, amount	$ 286,810,000		$ 286,810,000
Loan Modifications under CARES Act, Three Months
Loan Modifications under the CARES Act
Number of loans entered in to modification | loan	568		568
Loan modification, amount	$ 286,810,000		$ 286,810,000
Percent of portfolio	22.40%		22.40%
Loan Modifications under CARES Act, Three Months | Real Estate and Rental and Leasing
Loan Modifications under the CARES Act
Loan modification, amount	$ 158,326,000		$ 158,326,000
Loan Modifications under CARES Act, Three Months | Accommodations and Food Services
Loan Modifications under the CARES Act
Loan modification, amount	54,403,000		54,403,000
Loan Modifications under CARES Act, Three Months | Construction
Loan Modifications under the CARES Act
Loan modification, amount	17,182,000		17,182,000
Loan Modifications under CARES Act, Three Months | Manufacturing
Loan Modifications under the CARES Act
Loan modification, amount	9,091,000		9,091,000
Loan Modifications under CARES Act, Three Months | Other Services
Loan Modifications under the CARES Act
Loan modification, amount	7,961,000		7,961,000
Loan Modifications under CARES Act, Three Months | Cinemas
Loan Modifications under the CARES Act
Loan modification, amount	7,252,000		7,252,000
Loan Modifications under CARES Act, Three Months | Health Care and Social Assistance
Loan Modifications under the CARES Act
Loan modification, amount	7,560,000		7,560,000
Loan Modifications under CARES Act, Three Months | Retail Trade
Loan Modifications under the CARES Act
Loan modification, amount	5,184,000		5,184,000
Loan Modifications under CARES Act, Three Months | Arts, Entertainment, Recreation
Loan Modifications under the CARES Act
Loan modification, amount	4,444,000		4,444,000
Loan Modifications under CARES Act, Three Months | Non-NAICS (Consumer)
Loan Modifications under the CARES Act
Loan modification, amount	4,407,000		4,407,000
Loan Modifications under CARES Act, Three Months | Other
Loan Modifications under the CARES Act
Loan modification, amount	11,000,000		11,000,000
Loan Modifications under CARES Act, Three Months | Interest Only
Loan Modifications under the CARES Act
Loan modification, amount	$ 177,221,000		$ 177,221,000
Loan modification, percentage by industry category	61.80%		61.80%
Loan Modifications under CARES Act, Three Months | Interest Only | Real Estate and Rental and Leasing
Loan Modifications under the CARES Act
Loan modification, amount	$ 123,792,000		$ 123,792,000
Loan modification, percentage by industry category	43.20%		43.20%
Loan Modifications under CARES Act, Three Months | Interest Only | Accommodations and Food Services
Loan Modifications under the CARES Act
Loan modification, amount	$ 9,936,000		$ 9,936,000
Loan modification, percentage by industry category	3.50%		3.50%
Loan Modifications under CARES Act, Three Months | Interest Only | Construction
Loan Modifications under the CARES Act
Loan modification, amount	$ 8,758,000		$ 8,758,000
Loan modification, percentage by industry category	3.10%		3.10%
Loan Modifications under CARES Act, Three Months | Interest Only | Manufacturing
Loan Modifications under the CARES Act
Loan modification, amount	$ 8,002,000		$ 8,002,000
Loan modification, percentage by industry category	2.80%		2.80%
Loan Modifications under CARES Act, Three Months | Interest Only | Other Services
Loan Modifications under the CARES Act
Loan modification, amount	$ 6,141,000		$ 6,141,000
Loan modification, percentage by industry category	2.10%		2.10%
Loan Modifications under CARES Act, Three Months | Interest Only | Cinemas
Loan Modifications under the CARES Act
Loan modification, amount	$ 1,061,000		$ 1,061,000
Loan modification, percentage by industry category	0.40%		0.40%
Loan Modifications under CARES Act, Three Months | Interest Only | Health Care and Social Assistance
Loan Modifications under the CARES Act
Loan modification, amount	$ 6,367,000		$ 6,367,000
Loan modification, percentage by industry category	2.20%		2.20%
Loan Modifications under CARES Act, Three Months | Interest Only | Retail Trade
Loan Modifications under the CARES Act
Loan modification, amount	$ 4,338,000		$ 4,338,000
Loan modification, percentage by industry category	1.50%		1.50%
Loan Modifications under CARES Act, Three Months | Interest Only | Arts, Entertainment, Recreation
Loan Modifications under the CARES Act
Loan modification, amount	$ 1,235,000		$ 1,235,000
Loan modification, percentage by industry category	0.40%		0.40%
Loan Modifications under CARES Act, Three Months | Interest Only | Non-NAICS (Consumer)
Loan Modifications under the CARES Act
Loan modification, amount	$ 292,000		$ 292,000
Loan modification, percentage by industry category	0.10%		0.10%
Loan Modifications under CARES Act, Three Months | Interest Only | Other
Loan Modifications under the CARES Act
Loan modification, amount	$ 7,299,000		$ 7,299,000
Loan modification, percentage by industry category	2.50%		2.50%
Loan Modifications under CARES Act, Three Months | Full Deferral
Loan Modifications under the CARES Act
Loan modification, amount	$ 109,589,000		$ 109,589,000
Loan modification, percentage by industry category	38.20%		38.20%
Loan Modifications under CARES Act, Three Months | Full Deferral | Real Estate and Rental and Leasing
Loan Modifications under the CARES Act
Loan modification, amount	$ 34,534,000		$ 34,534,000
Loan modification, percentage by industry category	12.00%		12.00%
Loan Modifications under CARES Act, Three Months | Full Deferral | Accommodations and Food Services
Loan Modifications under the CARES Act
Loan modification, amount	$ 44,467,000		$ 44,467,000
Loan modification, percentage by industry category	15.50%		15.50%
Loan Modifications under CARES Act, Three Months | Full Deferral | Construction
Loan Modifications under the CARES Act
Loan modification, amount	$ 8,424,000		$ 8,424,000
Loan modification, percentage by industry category	2.90%		2.90%
Loan Modifications under CARES Act, Three Months | Full Deferral | Manufacturing
Loan Modifications under the CARES Act
Loan modification, amount	$ 1,089,000		$ 1,089,000
Loan modification, percentage by industry category	0.40%		0.40%
Loan Modifications under CARES Act, Three Months | Full Deferral | Other Services
Loan Modifications under the CARES Act
Loan modification, amount	$ 1,820,000		$ 1,820,000
Loan modification, percentage by industry category	0.60%		0.60%
Loan Modifications under CARES Act, Three Months | Full Deferral | Cinemas
Loan Modifications under the CARES Act
Loan modification, amount	$ 6,191,000		$ 6,191,000
Loan modification, percentage by industry category	2.20%		2.20%
Loan Modifications under CARES Act, Three Months | Full Deferral | Health Care and Social Assistance
Loan Modifications under the CARES Act
Loan modification, amount	$ 1,193,000		$ 1,193,000
Loan modification, percentage by industry category	0.40%		0.40%
Loan Modifications under CARES Act, Three Months | Full Deferral | Retail Trade
Loan Modifications under the CARES Act
Loan modification, amount	$ 846,000		$ 846,000
Loan modification, percentage by industry category	0.30%		0.30%
Loan Modifications under CARES Act, Three Months | Full Deferral | Arts, Entertainment, Recreation
Loan Modifications under the CARES Act
Loan modification, amount	$ 3,209,000		$ 3,209,000
Loan modification, percentage by industry category	1.10%		1.10%
Loan Modifications under CARES Act, Three Months | Full Deferral | Non-NAICS (Consumer)
Loan Modifications under the CARES Act
Loan modification, amount	$ 4,115,000		$ 4,115,000
Loan modification, percentage by industry category	1.40%		1.40%
Loan Modifications under CARES Act, Three Months | Full Deferral | Other
Loan Modifications under the CARES Act
Loan modification, amount	$ 3,701,000		$ 3,701,000
Loan modification, percentage by industry category	1.30%		1.30%
Loan Modifications under CARES Act, Six Months
Loan Modifications under the CARES Act
Number of loans entered in to modification	40		40
Loan modification, amount	$ 58,333,000		$ 58,333,000
Percent of portfolio	4.60%		4.60%
Percent of modifications			20.30%
Loan Modifications under CARES Act, Six Months | Real Estate and Rental and Leasing
Loan Modifications under the CARES Act
Loan modification, amount	$ 20,490,000		$ 20,490,000
Loan Modifications under CARES Act, Six Months | Accommodations and Food Services
Loan Modifications under the CARES Act
Loan modification, amount	29,528,000		29,528,000
Loan Modifications under CARES Act, Six Months | Construction
Loan Modifications under the CARES Act
Loan modification, amount	1,225,000		1,225,000
Loan Modifications under CARES Act, Six Months | Cinemas
Loan Modifications under the CARES Act
Loan modification, amount	6,191,000		6,191,000
Loan Modifications under CARES Act, Six Months | Retail Trade
Loan Modifications under the CARES Act
Loan modification, amount	119,000		119,000
Loan Modifications under CARES Act, Six Months | Arts, Entertainment, Recreation
Loan Modifications under the CARES Act
Loan modification, amount	65,000		65,000
Loan Modifications under CARES Act, Six Months | Non-NAICS (Consumer)
Loan Modifications under the CARES Act
Loan modification, amount	142,000		142,000
Loan Modifications under CARES Act, Six Months | Other
Loan Modifications under the CARES Act
Loan modification, amount	573,000		573,000
Loan Modifications under CARES Act, Six Months | Interest Only
Loan Modifications under the CARES Act
Loan modification, amount	$ 22,582,000		$ 22,582,000
Loan modification, percentage by industry category	38.70%		38.70%
Loan Modifications under CARES Act, Six Months | Interest Only | Real Estate and Rental and Leasing
Loan Modifications under the CARES Act
Loan modification, amount	$ 14,700,000		$ 14,700,000
Loan modification, percentage by industry category	25.20%		25.20%
Loan Modifications under CARES Act, Six Months | Interest Only | Accommodations and Food Services
Loan Modifications under the CARES Act
Loan modification, amount	$ 7,059,000		$ 7,059,000
Loan modification, percentage by industry category	12.10%		12.10%
Loan Modifications under CARES Act, Six Months | Interest Only | Construction
Loan Modifications under the CARES Act
Loan modification, amount	$ 505,000		$ 505,000
Loan modification, percentage by industry category	0.90%		0.90%
Loan Modifications under CARES Act, Six Months | Interest Only | Arts, Entertainment, Recreation
Loan Modifications under the CARES Act
Loan modification, amount	$ 65,000		$ 65,000
Loan modification, percentage by industry category	0.10%		0.10%
Loan Modifications under CARES Act, Six Months | Interest Only | Other
Loan Modifications under the CARES Act
Loan modification, amount	$ 253,000		$ 253,000
Loan modification, percentage by industry category	0.40%		0.40%
Loan Modifications under CARES Act, Six Months | Full Deferral
Loan Modifications under the CARES Act
Loan modification, amount	$ 35,751,000		$ 35,751,000
Loan modification, percentage by industry category	61.30%		61.30%
Loan Modifications under CARES Act, Six Months | Full Deferral | Real Estate and Rental and Leasing
Loan Modifications under the CARES Act
Loan modification, amount	$ 5,790,000		$ 5,790,000
Loan modification, percentage by industry category	9.90%		9.90%
Loan Modifications under CARES Act, Six Months | Full Deferral | Accommodations and Food Services
Loan Modifications under the CARES Act
Loan modification, amount	$ 22,469,000		$ 22,469,000
Loan modification, percentage by industry category	38.50%		38.50%
Loan Modifications under CARES Act, Six Months | Full Deferral | Construction
Loan Modifications under the CARES Act
Loan modification, amount	$ 720,000		$ 720,000
Loan modification, percentage by industry category	1.20%		1.20%
Loan Modifications under CARES Act, Six Months | Full Deferral | Cinemas
Loan Modifications under the CARES Act
Loan modification, amount	$ 6,191,000		$ 6,191,000
Loan modification, percentage by industry category	10.60%		10.60%
Loan Modifications under CARES Act, Six Months | Full Deferral | Retail Trade
Loan Modifications under the CARES Act
Loan modification, amount	$ 119,000		$ 119,000
Loan modification, percentage by industry category	0.20%		0.20%
Loan Modifications under CARES Act, Six Months | Full Deferral | Non-NAICS (Consumer)
Loan Modifications under the CARES Act
Loan modification, amount	$ 142,000		$ 142,000
Loan modification, percentage by industry category	0.30%		0.30%
Loan Modifications under CARES Act, Six Months | Full Deferral | Other
Loan Modifications under the CARES Act
Loan modification, amount	$ 320,000		$ 320,000
Loan modification, percentage by industry category	0.60%		0.60%
90 days or more past due
Troubled Debt Restructurings
Number of contracts called for default and charged off | contract	1	0	1	0
Commercial, financial, and agricultural
Troubled Debt Restructurings
Number of Contracts | contract				2
Pre- Modification				$ 80,000
Post- Modification				$ 80,000
Loan Modifications under the CARES Act
Total loans held for investment	$ 296,323,000		$ 296,323,000		199,022,000
Residential real estate | Mortgages
Troubled Debt Restructurings
Number of Contracts | contract	1		1
Pre- Modification	$ 111,000		$ 111,000
Post- Modification	119,000		119,000
Loan Modifications under the CARES Act
Total loans held for investment	250,452,000		250,452,000		252,643,000
Commercial real estate | Mortgages
Loan Modifications under the CARES Act
Total loans held for investment	592,855,000		$ 592,855,000		576,635,000
Installment and other consumer
Troubled Debt Restructurings
Number of Contracts | contract			1
Pre- Modification			$ 6,000
Post- Modification			5,000
Loan Modifications under the CARES Act
Total loans held for investment	28,788,000		28,788,000		32,464,000
Performing TDRs
Troubled Debt Restructurings
Troubled debt restructurings	2,500,000		2,500,000		2,500,000
Non-performing TDRs - 90 days past due
Troubled Debt Restructurings
Troubled debt restructurings	$ 1,300,000		$ 1,300,000		$ 1,600,000