CONSOLIDATED STATEMENTS OF SHAREHOLDERS' EQUITY - USD ($)	Common Stock [Member]	Capital Contributed in Excess of Par Value [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Loss [Member]	Treasury Stock [Member]	Total
Balance at Apr. 30, 2018	$ 832,000	$ 50,922,000	$ 47,525,000	$ (7,934,000)	$ (4,215,000)	$ 87,130,000
Balance (in shares) at Apr. 30, 2018	8,324
Issuance of restricted common stock	$ 3,000	203,000	0	0	0	206,000
Issuance of restricted common stock (in shares)	29
Issuance of deferred stock units	$ 0	80,000	0	0	0	80,000
Issuance of deferred stock units (in shares)	0
Net income (loss)	$ 0	0	1,527,000	0	0	1,527,000
Other comprehensive income	0	0	0	903,000	0	903,000
Balance at Apr. 30, 2019	$ 835,000	51,205,000	49,052,000	(7,031,000)	(4,215,000)	89,846,000
Balance (in shares) at Apr. 30, 2019	8,353
Issuance of restricted common stock	$ 1,000	29,000	0	0	0	30,000
Issuance of restricted common stock (in shares)	5
Issuance of deferred stock units	$ 0	100,000	0	0	0	100,000
Issuance of deferred stock units (in shares)	0
Net income (loss)	$ 0	0	(5,903,000)	0	0	(5,903,000)
Other comprehensive income	0	0	0	564,000	0	564,000
Balance at Apr. 30, 2020	$ 836,000	$ 51,334,000	$ 43,149,000	$ (6,467,000)	$ (4,215,000)	$ 84,637,000
Balance (in shares) at Apr. 30, 2020	8,358