Note H - Revenue - Disaggregation of Revenue (Details) - USD ($)	3 Months Ended		6 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Net sales	$ 39,995,580	$ 53,432,029	$ 80,970,900	$ 101,625,347
Coil [Member]
Net sales	28,420,609	34,828,444	56,602,077	65,957,644
Coil [Member] | Prime Coil [Member]
Net sales	24,936,635	29,575,814	49,165,088	54,351,845
Coil [Member] | Secondary Coil [Member]
Net sales	3,271,453	4,894,421	7,043,968	11,004,879
Coil [Member] | Customer Owned [Member]
Net sales	212,521	358,209	393,021	600,920
Tubular [Member]
Net sales	11,574,971	18,603,585	24,368,823	35,667,703
Tubular [Member] | Manufactured Pipe [Member]
Net sales	9,744,189	14,214,209	20,476,676	25,169,596
Tubular [Member] | Mill Reject Pipe [Member]
Net sales	1,830,782	4,306,980	3,892,147	9,727,841
Tubular [Member] | Pipe Finishing Services [Member]
Net sales		$ 82,396		$ 770,266