BENEFIT PLANS - Additional information (Details) - USD ($)	1 Months Ended		3 Months Ended		6 Months Ended
	Oct. 31, 2020	Sep. 30, 2020	Oct. 31, 2021	Oct. 31, 2020	Oct. 31, 2021	Oct. 31, 2020
Defined Benefit Plan Disclosure [Line Items]
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent			$ 67,000	$ 90,000	$ 133,000	$ 180,000
Share-based Compensation, Total					47,000	42,000
Issuance of common stock settled from deferred common share units (in shares)	12,411
Issuance of common stock settled from deferred common share units		$ 20,000
Accrued compensation expense related to the deferred stock units					75,000	82,000
Board of Directors Chairman [Member]
Defined Benefit Plan Disclosure [Line Items]
Non Cash Director Fee Compensation			22,000	21,000	$ 45,000	35,000
PBGC [Member]
Defined Benefit Plan Disclosure [Line Items]
Payment for Pension Benefits				1,847,000		1,847,000
Restricted Stock [Member]
Defined Benefit Plan Disclosure [Line Items]
Weighted-average remaining vesting period					3 years
Restricted Stock [Member] | Equity Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Share-based Compensation, Total			31,000	25,000	$ 47,000	54,000
Unrecognized compensation expense related to restricted shares	$ 73,000		$ 137,000	$ 73,000	$ 137,000	$ 73,000