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, 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 common stock units	$ 0	100,000	0	0	0	100,000
Issuance of deferred common share 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
Issuance of restricted common stock	$ 1,000	41,000	0	0	0	42,000
Issuance of restricted common stock (in shares)	9
Issuance of deferred common stock units	$ 0	90,000	0	0	0	90,000
Issuance of deferred common share units (in shares)	0
Issuance of deferred common share units	$ 0	0	0	0	0
Issuance of deferred common share units (in shares)	12
Repurchase of common stock	$ (83,000)	(5,033,000)	0	0	0	(5,116,000)
Repurchase of common stock (in shares)	(831)
Retirement of treasury stock	$ (24,000)	(1,360,000)	(2,831,000)	0	4,215,000
Retirement of treasury stock (in shares)	(225)
Net income (loss)	$ 0	0	7,392,000	0	0	7,392,000
Other comprehensive income	0	0	0	1,844,000	0	1,844,000
Balance at Apr. 30, 2021	$ 730,000	$ 45,072,000	$ 47,710,000	$ (4,623,000)	$ 0	$ 88,889,000
Balance (in shares) at Apr. 30, 2021	7,323