Fair Value Measurements - Impaired Loans Remeasured and Reported at Fair Value of Underlying Collateral (Detail) - USD ($) $ in Thousands	Mar. 31, 2020	Mar. 31, 2019
Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Carrying value of impaired loans before allocations	$ 1,919	$ 11,487
Specific valuation allowance allocations	70	(256)
Loans receivable, fair value disclosure	1,989	11,231
Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Carrying value of impaired loans before allocations	3,867	37,525
Specific valuation allowance allocations	(244)	(3,441)
Loans receivable, fair value disclosure	$ 3,623	$ 34,084