FAIR VALUE MEASUREMENTS - Level 3 inputs for financial instruments measured at fair value (Details) - Nonrecurring basis - Level 3 - Impaired loans - Discounted cash flows - Discount rate		9 Months Ended	12 Months Ended
		Dec. 31, 2019	Mar. 31, 2020
Minimum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans	[1]	6.25%	6.25%
Maximum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans	[1]	8.00%	8.00%

[1] There were no adjustments to appraised values of impaired loans as of December 31, 2019 and March 31, 2019.