Fair Value Measurements - Narrative (Details) $ in Thousands	9 Months Ended
	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)
Guarantees of Farmers | Discounted Cash Flow Valuation Technique | Minimum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis, Valuation Techniques [Line Items]
Market interest rate (as a percent)	15.00%
Guarantees of Farmers | Discounted Cash Flow Valuation Technique | Maximum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis, Valuation Techniques [Line Items]
Market interest rate (as a percent)	75.80%
Securitized Beneficial Interests
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis, Valuation Techniques [Line Items]
Unrealized losses for securitized beneficial interests	$ 691	$ 643
Securitized Beneficial Interests | Minimum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis, Valuation Techniques [Line Items]
Payment speed	77 days
Discount rate (as a percent)	1.70%
Securitized Beneficial Interests | Maximum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis, Valuation Techniques [Line Items]
Payment speed	80 days
Discount rate (as a percent)	4.30%
Loss Severity | Guarantees of Farmers | Historical Loss Valuation Technique | Minimum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis, Valuation Techniques [Line Items]
Historical loss (as a percent)	0.022
Loss Severity | Guarantees of Farmers | Historical Loss Valuation Technique | Maximum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis, Valuation Techniques [Line Items]
Historical loss (as a percent)	0.100