Loans Held for Investment - Schedule of Troubled Debt Restructurings (Details) $ in Millions	3 Months Ended
	Mar. 31, 2022 USD ($) note
Loans and Leases Receivable, Troubled Debt Restructuring [Line Items]
Number of Notes | note	5
Troubled debt restructurings	$ 17.2
Interest only period
Loans and Leases Receivable, Troubled Debt Restructuring [Line Items]
Troubled debt restructurings	3.2
Extension of term or amortization schedule
Loans and Leases Receivable, Troubled Debt Restructuring [Line Items]
Troubled debt restructurings	13.6
Interest rate adjustment
Loans and Leases Receivable, Troubled Debt Restructuring [Line Items]
Troubled debt restructurings	0.0
Other Loan Restructuring Modification
Loans and Leases Receivable, Troubled Debt Restructuring [Line Items]
Troubled debt restructurings	$ 0.4
Commercial Real Estate
Loans and Leases Receivable, Troubled Debt Restructuring [Line Items]
Number of Notes | note	2
Troubled debt restructurings	$ 7.4
Commercial Real Estate | Interest only period
Loans and Leases Receivable, Troubled Debt Restructuring [Line Items]
Troubled debt restructurings	3.2
Commercial Real Estate | Extension of term or amortization schedule
Loans and Leases Receivable, Troubled Debt Restructuring [Line Items]
Troubled debt restructurings	4.2
Commercial Real Estate | Interest rate adjustment
Loans and Leases Receivable, Troubled Debt Restructuring [Line Items]
Troubled debt restructurings	0.0
Commercial Real Estate | Other Loan Restructuring Modification
Loans and Leases Receivable, Troubled Debt Restructuring [Line Items]
Troubled debt restructurings	$ 0.0
Residential
Loans and Leases Receivable, Troubled Debt Restructuring [Line Items]
Number of Notes | note	1
Troubled debt restructurings	$ 0.5
Residential | Interest only period
Loans and Leases Receivable, Troubled Debt Restructuring [Line Items]
Troubled debt restructurings	0.0
Residential | Extension of term or amortization schedule
Loans and Leases Receivable, Troubled Debt Restructuring [Line Items]
Troubled debt restructurings	0.5
Residential | Interest rate adjustment
Loans and Leases Receivable, Troubled Debt Restructuring [Line Items]
Troubled debt restructurings	0.0
Residential | Other Loan Restructuring Modification
Loans and Leases Receivable, Troubled Debt Restructuring [Line Items]
Troubled debt restructurings	$ 0.0
Agricultural
Loans and Leases Receivable, Troubled Debt Restructuring [Line Items]
Number of Notes | note	1
Troubled debt restructurings	$ 8.9
Agricultural | Interest only period
Loans and Leases Receivable, Troubled Debt Restructuring [Line Items]
Troubled debt restructurings	0.0
Agricultural | Extension of term or amortization schedule
Loans and Leases Receivable, Troubled Debt Restructuring [Line Items]
Troubled debt restructurings	8.9
Agricultural | Interest rate adjustment
Loans and Leases Receivable, Troubled Debt Restructuring [Line Items]
Troubled debt restructurings	0.0
Agricultural | Other Loan Restructuring Modification
Loans and Leases Receivable, Troubled Debt Restructuring [Line Items]
Troubled debt restructurings	$ 0.0
Commercial
Loans and Leases Receivable, Troubled Debt Restructuring [Line Items]
Number of Notes | note	1
Troubled debt restructurings	$ 0.4
Commercial | Interest only period
Loans and Leases Receivable, Troubled Debt Restructuring [Line Items]
Troubled debt restructurings	0.0
Commercial | Extension of term or amortization schedule
Loans and Leases Receivable, Troubled Debt Restructuring [Line Items]
Troubled debt restructurings	0.0
Commercial | Interest rate adjustment
Loans and Leases Receivable, Troubled Debt Restructuring [Line Items]
Troubled debt restructurings	0.0
Commercial | Other Loan Restructuring Modification
Loans and Leases Receivable, Troubled Debt Restructuring [Line Items]
Troubled debt restructurings	$ 0.4