Note G - Segment Information - Segment Information (Details) - USD ($)	3 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Mar. 31, 2018
Total Net Sales	$ 48,193,318	$ 23,083,269
Operating profit (loss)	4,699,738	504,916
Interest & other income	(62,775)	(4,375)
Earnings before income taxes	4,762,513	509,291
Assets	95,900,901		$ 81,653,307
Coil [Member]
Total Net Sales	31,129,200	18,009,835
Tubular [Member]
Total Net Sales	17,064,118	5,073,434
Operating Segments [Member]
Operating profit (loss)	5,500,000	1,032,000
Assets	92,330,000		77,369,000
Operating Segments [Member] | Coil [Member]
Total Net Sales	31,129,000	18,010,000
Operating profit (loss)	3,179,000	1,033,000
Assets	45,895,000		34,359,000
Operating Segments [Member] | Tubular [Member]
Total Net Sales	17,064,000	5,073,000
Operating profit (loss)	2,321,000	(1,000)
Assets	46,435,000		43,010,000
Corporate, Non-Segment [Member]
Corporate expenses	800,000	$ 527,000
Assets	$ 3,571,000		$ 4,284,000