Condensed Consolidated Statements of Equity (Unaudited) - USD ($) $ in Thousands	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Treasury Stock [Member]	Noncontrolling Interest [Member]	Total
Balance (in shares) at Apr. 30, 2021	13,591,889
Balance at Apr. 30, 2021	$ 136	$ 98,812	$ 570,505	$ (257,527)	$ 100	$ 412,026
Issuance of common stock (in shares)	673
Issuance of common stock		81				81
Stock options exercised (in shares)	15,281
Stock options exercised		(1,007)				(1,007)
Purchase of treasury shares				(11,618)		(11,618)
Stock based compensation		2,972				2,972
Dividends on subsidiary preferred stock			(10)			(10)
Net income			26,054			26,054
Balance (in shares) at Jul. 31, 2021	13,607,843
Balance at Jul. 31, 2021	$ 136	100,858	596,549	(269,145)	100	428,498
Balance (in shares) at Apr. 30, 2021	13,591,889
Balance at Apr. 30, 2021	$ 136	98,812	570,505	(257,527)	100	412,026
Net income						49,479
Balance (in shares) at Oct. 31, 2021	13,623,410
Balance at Oct. 31, 2021	$ 136	101,903	619,964	(277,490)	100	444,613
Balance (in shares) at Jul. 31, 2021	13,607,843
Balance at Jul. 31, 2021	$ 136	100,858	596,549	(269,145)	100	428,498
Issuance of common stock (in shares)	7,186
Issuance of common stock		68				68
Stock options exercised (in shares)	8,381
Purchase of treasury shares				(8,345)		(8,345)
Stock based compensation		977				977
Dividends on subsidiary preferred stock			(10)			(10)
Net income			23,425			23,425
Balance (in shares) at Oct. 31, 2021	13,623,410
Balance at Oct. 31, 2021	$ 136	101,903	619,964	(277,490)	100	444,613
Balance (in shares) at Apr. 30, 2022	13,642,185
Balance at Apr. 30, 2022	$ 136	103,113	665,410	(292,225)	100	476,534
Issuance of common stock (in shares)	30,484
Issuance of common stock	$ 1	84	0	0	0	85
Stock options exercised (in shares)	23,000
Stock options exercised	$ 0	1,216	0	0	0	1,216
Purchase of treasury shares	0	0	0	(5,196)	0	(5,196)
Stock based compensation	0	1,978	0	0	0	1,978
Dividends on subsidiary preferred stock	0	0	(10)	0	0	(10)
Net income	$ 0	0	13,697	0	0	13,697
Balance (in shares) at Jul. 31, 2022	13,695,669
Balance at Jul. 31, 2022	$ 137	106,391	679,097	(297,421)	100	488,304
Balance (in shares) at Apr. 30, 2022	13,642,185
Balance at Apr. 30, 2022	$ 136	103,113	665,410	(292,225)	100	476,534
Net income						16,836
Balance (in shares) at Oct. 31, 2022	13,696,904
Balance at Oct. 31, 2022	$ 137	107,275	682,226	(297,421)	100	492,317
Balance (in shares) at Jul. 31, 2022	13,695,669
Balance at Jul. 31, 2022	$ 137	106,391	679,097	(297,421)	100	488,304
Issuance of common stock (in shares)	1,235
Issuance of common stock	$ 0	64	0	0	0	64
Stock based compensation	0	820	0	0	0	820
Dividends on subsidiary preferred stock	0	0	(10)	0	0	(10)
Net income	$ 0	0	3,139	0	0	3,139
Balance (in shares) at Oct. 31, 2022	13,696,904
Balance at Oct. 31, 2022	$ 137	$ 107,275	$ 682,226	$ (297,421)	$ 100	$ 492,317