BENEFIT PLANS - Additional information (Details) - USD ($)	1 Months Ended	3 Months Ended		9 Months Ended
	Nov. 30, 2021	Jan. 31, 2023	Jan. 31, 2022	Jan. 31, 2023	Jan. 31, 2022
BENEFIT PLANS
Pension plan net of tax, other comprehensive income		$ 65,000	$ 67,000	$ 208,000	$ 200,000
Share-based compensation				198,000	178,000
Pension settlement expense		2,336,000		2,336,000
Aggregate defined benefit pension plan		4,653,000		4,653,000
Board of Directors Chairman
BENEFIT PLANS
Director compensation non-cash expense		23,000	23,000	68,000	68,000
Accrued compensation expense related to the deferred stock units		8,000	8,000
Equity plan | President and Chief executive officer
BENEFIT PLANS
Stock option issued during the year	50,000
Exercise price	$ 14.24
2016 Equity Plan | Board of Directors Chairman
BENEFIT PLANS
Non cash compensation expense		13,000	16,000	38,000	16,000
Restricted stock | Equity plan
BENEFIT PLANS
Share-based compensation		39,000	25,000	101,000	72,000
Unrecognized compensation expense related to restricted shares		$ 143,000	$ 111,000	$ 143,000	$ 111,000
Weighted-average remaining vesting period				3 years