FAIR VALUE MEASUREMENTS - Narrative (Details) $ in Thousands	9 Months Ended		12 Months Ended
	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Mar. 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)	70.00%
Securitized Beneficial Interests
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis, Valuation Techniques [Line Items]
Unrealized losses for securitized beneficial interests	$ 643	$ 650	$ 2,531
Securitized Beneficial Interests | Minimum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis, Valuation Techniques [Line Items]
Payment speed	64 days
Discount rate (as a percent)	5.00%
Securitized Beneficial Interests | Maximum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis, Valuation Techniques [Line Items]
Payment speed	73 days
Discount rate (as a percent)	7.30%
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)	0.024
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