Fair Value Measurements - Information about Fair Value Measurements using Significant Unobservable Inputs (Details) $ in Thousands	12 Months Ended
	Mar. 31, 2021 USD ($)	Mar. 31, 2020 USD ($)
Discounted Cash Flow | Securitized Beneficial Interests
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis, Valuation Techniques [Line Items]
Fair value of unobservable inputs of asset	$ 19,370	$ 27,021
Discounted Cash Flow | Guarantees of Farmers
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis, Valuation Techniques [Line Items]
Fair value of unobservable inputs of asset		$ 255
Discounted Cash Flow | Minimum | Securitized Beneficial Interests
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis, Valuation Techniques [Line Items]
Securitized market rate (as a percent)	1.33%	3.44%
Payment speed period	57 days	77 days
Discounted Cash Flow | Minimum | Guarantees of Farmers
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis, Valuation Techniques [Line Items]
Market interest rate (as a percent)		15.00%
Discounted Cash Flow | Maximum | Securitized Beneficial Interests
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis, Valuation Techniques [Line Items]
Securitized market rate (as a percent)	3.56%	3.45%
Payment speed period	77 days	100 days
Discounted Cash Flow | Maximum | Guarantees of Farmers
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis, Valuation Techniques [Line Items]
Market interest rate (as a percent)		75.80%
Historical Loss | Guarantees of Farmers
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis, Valuation Techniques [Line Items]
Fair value of unobservable inputs of asset	$ 1,740	$ 2,536
Historical Loss | Minimum | Guarantees of Farmers
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis, Valuation Techniques [Line Items]
Historical loss rate (as a percent)	0.05%	2.20%
Historical Loss | Maximum | Guarantees of Farmers
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis, Valuation Techniques [Line Items]
Historical loss rate (as a percent)	45.20%	10.00%
Discounted Future Payments | Long-Term Debt
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis, Valuation Techniques [Line Items]
Fair value of unobservable inputs of liability	$ 3,162
Discounted Future Payments | Minimum | Treasury Notes Rate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis, Valuation Techniques [Line Items]
Measurement input of long-term debt (as a percent)	0.0094
Discounted Future Payments | Minimum | Borrowing Rate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis, Valuation Techniques [Line Items]
Measurement input of long-term debt (as a percent)	0.0700
Discounted Future Payments | Maximum | Treasury Notes Rate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis, Valuation Techniques [Line Items]
Measurement input of long-term debt (as a percent)	0.0158
Discounted Future Payments | Maximum | Borrowing Rate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis, Valuation Techniques [Line Items]
Measurement input of long-term debt (as a percent)	0.1072