Loans Held for Investment - Schedule of Modifications to Borrowers (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2023	Dec. 31, 2022
Financing Receivable, Modifications to Borrowers [Line Items]
Interest Receivable	$ 113.7	$ 118.3
Borrowers in Financial Distress
Financing Receivable, Modifications to Borrowers [Line Items]
Financing Receivable, Excluding Accrued Interest, Modified Period, Principal Forgiveness	1.7
Financing Receivable, Excluding Accrued Interest, Modified Period	27.2
Financing Receivable, Excluding Accrued Interest, Modified Period, Term Extension	$ 25.5
Financing Receivable, Modification to Total Financing Receivables, Excluding Accrued Interest, Percent	0.20%
Interest Receivable	$ 0.3
Borrowers in Financial Difficulty
Financing Receivable, Modifications to Borrowers [Line Items]
Financing Receivable, Excluding Accrued Interest, Modified Period, Principal Forgiveness	1.6
Non-owner occupied | Borrowers in Financial Distress
Financing Receivable, Modifications to Borrowers [Line Items]
Financing Receivable, Excluding Accrued Interest, Modified Period, Principal Forgiveness	$ 0.0
Financing Receivable, Excluding Accrued Interest, Modified Period, Term Extension, Weighted-Average Months	4 years
Financing Receivable, Excluding Accrued Interest, Modified Period	$ 2.4
Financing Receivable, Excluding Accrued Interest, Modified Period, Term Extension	$ 2.4
Financing Receivable, Modification to Total Financing Receivables, Excluding Accrued Interest, Percent	0.10%
Non-owner occupied | Borrowers in Financial Difficulty
Financing Receivable, Modifications to Borrowers [Line Items]
Financing Receivable, Excluding Accrued Interest, Modified Period, Principal Forgiveness	$ 0.0
Land acquisition & development | Borrowers in Financial Distress
Financing Receivable, Modifications to Borrowers [Line Items]
Financing Receivable, Excluding Accrued Interest, Modified Period, Principal Forgiveness	$ 0.0
Financing Receivable, Excluding Accrued Interest, Modified Period, Term Extension, Weighted-Average Months	12 years 4 months 24 days
Financing Receivable, Excluding Accrued Interest, Modified Period	$ 0.2
Financing Receivable, Excluding Accrued Interest, Modified Period, Term Extension	$ 0.2
Financing Receivable, Modification to Total Financing Receivables, Excluding Accrued Interest, Percent	0.10%
Land acquisition & development | Borrowers in Financial Difficulty
Financing Receivable, Modifications to Borrowers [Line Items]
Financing Receivable, Excluding Accrued Interest, Modified Period, Principal Forgiveness	$ 0.0
Home equity and HELOC | Borrowers in Financial Distress
Financing Receivable, Modifications to Borrowers [Line Items]
Financing Receivable, Excluding Accrued Interest, Modified Period, Principal Forgiveness	$ 0.1
Financing Receivable, Excluding Accrued Interest, Modified Period, Term Extension, Weighted-Average Months	37 years 7 months 6 days
Financing Receivable, Excluding Accrued Interest, Modified Period	$ 0.1
Financing Receivable, Excluding Accrued Interest, Modified Period, Term Extension	$ 0.0
Financing Receivable, Modification to Total Financing Receivables, Excluding Accrued Interest, Percent	0.00%
Home equity and HELOC | Borrowers in Financial Difficulty
Financing Receivable, Modifications to Borrowers [Line Items]
Financing Receivable, Excluding Accrued Interest, Modified Period, Principal Forgiveness	$ 0.3
Agricultural | Borrowers in Financial Distress
Financing Receivable, Modifications to Borrowers [Line Items]
Financing Receivable, Excluding Accrued Interest, Modified Period, Principal Forgiveness	$ 0.0
Financing Receivable, Excluding Accrued Interest, Modified Period, Term Extension, Weighted-Average Months	7 years 2 months 12 days
Financing Receivable, Excluding Accrued Interest, Modified Period	$ 1.2
Financing Receivable, Excluding Accrued Interest, Modified Period, Term Extension	$ 1.2
Financing Receivable, Modification to Total Financing Receivables, Excluding Accrued Interest, Percent	0.20%
Agricultural | Borrowers in Financial Difficulty
Financing Receivable, Modifications to Borrowers [Line Items]
Financing Receivable, Excluding Accrued Interest, Modified Period, Principal Forgiveness	$ 0.0
Commercial and floor plans | Borrowers in Financial Distress
Financing Receivable, Modifications to Borrowers [Line Items]
Financing Receivable, Excluding Accrued Interest, Modified Period, Principal Forgiveness	$ 0.0
Financing Receivable, Excluding Accrued Interest, Modified Period, Term Extension, Weighted-Average Months	11 years 6 months
Financing Receivable, Excluding Accrued Interest, Modified Period	$ 2.0
Financing Receivable, Excluding Accrued Interest, Modified Period, Term Extension	$ 2.0
Financing Receivable, Modification to Total Financing Receivables, Excluding Accrued Interest, Percent	0.10%
Commercial and floor plans | Borrowers in Financial Difficulty
Financing Receivable, Modifications to Borrowers [Line Items]
Financing Receivable, Excluding Accrued Interest, Modified Period, Principal Forgiveness	$ 0.0
Commercial purpose secured by 1-4 family | Borrowers in Financial Distress
Financing Receivable, Modifications to Borrowers [Line Items]
Financing Receivable, Excluding Accrued Interest, Modified Period, Principal Forgiveness	$ 0.0
Financing Receivable, Excluding Accrued Interest, Modified Period, Term Extension, Weighted-Average Months	8 years 8 months 12 days
Financing Receivable, Excluding Accrued Interest, Modified Period	$ 0.6
Financing Receivable, Excluding Accrued Interest, Modified Period, Term Extension	$ 0.6
Financing Receivable, Modification to Total Financing Receivables, Excluding Accrued Interest, Percent	0.10%
Commercial purpose secured by 1-4 family | Borrowers in Financial Difficulty
Financing Receivable, Modifications to Borrowers [Line Items]
Financing Receivable, Excluding Accrued Interest, Modified Period, Principal Forgiveness	$ 0.0
Agricultural | Borrowers in Financial Distress
Financing Receivable, Modifications to Borrowers [Line Items]
Financing Receivable, Excluding Accrued Interest, Modified Period, Principal Forgiveness	$ 0.0
Financing Receivable, Excluding Accrued Interest, Modified Period, Term Extension, Weighted-Average Months	9 years 3 months 18 days
Financing Receivable, Excluding Accrued Interest, Modified Period	$ 17.8
Financing Receivable, Excluding Accrued Interest, Modified Period, Term Extension	$ 17.8
Financing Receivable, Modification to Total Financing Receivables, Excluding Accrued Interest, Percent	2.70%
Agricultural | Borrowers in Financial Difficulty
Financing Receivable, Modifications to Borrowers [Line Items]
Financing Receivable, Excluding Accrued Interest, Modified Period, Principal Forgiveness	$ 0.0
Owner occupied | Borrowers in Financial Distress
Financing Receivable, Modifications to Borrowers [Line Items]
Financing Receivable, Excluding Accrued Interest, Modified Period, Principal Forgiveness	$ 1.6
Financing Receivable, Excluding Accrued Interest, Modified Period, Term Extension, Weighted-Average Months	9 years 8 months 12 days
Financing Receivable, Excluding Accrued Interest, Modified Period	$ 2.9
Financing Receivable, Excluding Accrued Interest, Modified Period, Term Extension	$ 1.3
Financing Receivable, Modification to Total Financing Receivables, Excluding Accrued Interest, Percent	0.10%
Owner occupied | Borrowers in Financial Difficulty
Financing Receivable, Modifications to Borrowers [Line Items]
Financing Receivable, Excluding Accrued Interest, Modified Period, Principal Forgiveness	$ 1.3