Loans and Allowance for Loan Losses - Aging of Past Due Loans by Class of Loan (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Financing Receivable, Past Due [Line Items]
Loans	$ 3,642,346	$ 3,657,779
Financial Asset, Current
Financing Receivable, Past Due [Line Items]
Loans	3,635,919	3,636,192
30-59 Days Past Due
Financing Receivable, Past Due [Line Items]
Loans	3,863	10,440
60-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Loans	1,278	7,437
Greater than 90 Days Past Due
Financing Receivable, Past Due [Line Items]
Loans	1,286	3,710
Financial Asset, Past Due
Financing Receivable, Past Due [Line Items]
Loans	6,427	21,587
Construction Real Estate Loans
Financing Receivable, Past Due [Line Items]
Loans	528,157	581,941
Construction Real Estate Loans | Financial Asset, Current
Financing Receivable, Past Due [Line Items]
Loans	527,975	581,388
Construction Real Estate Loans | 30-59 Days Past Due
Financing Receivable, Past Due [Line Items]
Loans	170	95
Construction Real Estate Loans | 60-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Loans	12	14
Construction Real Estate Loans | Greater than 90 Days Past Due
Financing Receivable, Past Due [Line Items]
Loans	0	444
Construction Real Estate Loans | Financial Asset, Past Due
Financing Receivable, Past Due [Line Items]
Loans	182	553
1-4 Family Residential Real Estate Loans
Financing Receivable, Past Due [Line Items]
Loans	678,402	719,952
1-4 Family Residential Real Estate Loans | Financial Asset, Current
Financing Receivable, Past Due [Line Items]
Loans	675,565	706,781
1-4 Family Residential Real Estate Loans | 30-59 Days Past Due
Financing Receivable, Past Due [Line Items]
Loans	1,563	7,872
1-4 Family Residential Real Estate Loans | 60-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Loans	522	2,469
1-4 Family Residential Real Estate Loans | Greater than 90 Days Past Due
Financing Receivable, Past Due [Line Items]
Loans	752	2,830
1-4 Family Residential Real Estate Loans | Financial Asset, Past Due
Financing Receivable, Past Due [Line Items]
Loans	2,837	13,171
Commercial Real Estate Loans
Financing Receivable, Past Due [Line Items]
Loans	1,430,900	1,295,746
Commercial Real Estate Loans | Financial Asset, Current
Financing Receivable, Past Due [Line Items]
Loans	1,429,986	1,294,878
Commercial Real Estate Loans | 30-59 Days Past Due
Financing Receivable, Past Due [Line Items]
Loans	687	467
Commercial Real Estate Loans | 60-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Loans	147	315
Commercial Real Estate Loans | Greater than 90 Days Past Due
Financing Receivable, Past Due [Line Items]
Loans	80	86
Commercial Real Estate Loans | Financial Asset, Past Due
Financing Receivable, Past Due [Line Items]
Loans	914	868
Commercial loans
Financing Receivable, Past Due [Line Items]
Loans	497,513	557,122
Commercial loans | Financial Asset, Current
Financing Receivable, Past Due [Line Items]
Loans	495,278	550,860
Commercial loans | 30-59 Days Past Due
Financing Receivable, Past Due [Line Items]
Loans	1,246	1,423
Commercial loans | 60-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Loans	535	4,516
Commercial loans | Greater than 90 Days Past Due
Financing Receivable, Past Due [Line Items]
Loans	454	323
Commercial loans | Financial Asset, Past Due
Financing Receivable, Past Due [Line Items]
Loans	2,235	6,262
Municipal loans
Financing Receivable, Past Due [Line Items]
Loans	417,398	409,028
Municipal loans | Financial Asset, Current
Financing Receivable, Past Due [Line Items]
Loans	417,398	408,964
Municipal loans | 30-59 Days Past Due
Financing Receivable, Past Due [Line Items]
Loans	0	64
Municipal loans | 60-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Loans	0	0
Municipal loans | Greater than 90 Days Past Due
Financing Receivable, Past Due [Line Items]
Loans	0	0
Municipal loans | Financial Asset, Past Due
Financing Receivable, Past Due [Line Items]
Loans	0	64
Loans to individuals
Financing Receivable, Past Due [Line Items]
Loans	89,976	93,990
Loans to individuals | Financial Asset, Current
Financing Receivable, Past Due [Line Items]
Loans	89,717	93,321
Loans to individuals | 30-59 Days Past Due
Financing Receivable, Past Due [Line Items]
Loans	197	519
Loans to individuals | 60-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Loans	62	123
Loans to individuals | Greater than 90 Days Past Due
Financing Receivable, Past Due [Line Items]
Loans	0	27
Loans to individuals | Financial Asset, Past Due
Financing Receivable, Past Due [Line Items]
Loans	$ 259	$ 669