Note J - Segment Information - Segment Information (Details) - USD ($)	3 Months Ended		6 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Mar. 31, 2021
Revenue from Contract with Customer, Including Assessed Tax	$ 92,570,895	$ 24,861,680	$ 158,487,334	$ 48,386,280
Operating profit (loss)	24,332,631	(317,046)	38,289,246	(1,457,999)
Corporate expenses	1,866,000	718,000	3,742,000	1,452,000
Interest expense	72,296	6,255	95,506	12,208
Other income (loss), net	(6,840,317)	4,325	(6,528,255)	8,648
Total earnings (loss) before income taxes	17,492,314	(312,721)	31,760,991	(1,449,351)
Segment assets	137,822,506		137,822,506		$ 95,008,809
Coil [Member]
Revenue from Contract with Customer, Including Assessed Tax	78,323,927	18,456,086	131,018,657	33,888,870
Tubular [Member]
Revenue from Contract with Customer, Including Assessed Tax	14,246,968	6,405,594	27,468,677	14,497,410
Operating Segments [Member]
Operating profit (loss)	26,270,000	407,000	42,127,000	6,000
Segment assets	130,225,000		130,225,000		74,554,000
Operating Segments [Member] | Coil [Member]
Revenue from Contract with Customer, Including Assessed Tax	78,324,000	18,456,000	131,019,000	33,889,000
Operating profit (loss)	24,273,000	751,000	37,529,000	291,000
Segment assets	112,826,000		112,826,000		56,670,000
Operating Segments [Member] | Tubular [Member]
Revenue from Contract with Customer, Including Assessed Tax	14,247,000	6,406,000	27,468,000	14,497,000
Operating profit (loss)	1,997,000	$ (344,000)	4,598,000	$ (285,000)
Segment assets	17,399,000		17,399,000		17,884,000
Corporate, Non-Segment [Member]
Segment assets	$ 7,598,000		$ 7,598,000		$ 20,455,000