Note F - Segment Information - Segment Information (Details) - USD ($)	3 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Mar. 31, 2017
Net Sales	$ 23,083,269	$ 22,393,764
Operating profit (loss)	225,029	(2,345,738)
Interest & other income	(4,375)	(14,750)
Earnings (loss) before income taxes	229,404	(2,330,988)
Assets	69,003,232		$ 63,263,297
Operating Segments [Member]
Operating profit (loss)	752,000	(1,789,000)
Assets	62,724,000		59,132,000
Operating Segments [Member] | Coil [Member]
Net Sales	18,010,000	18,999,000
Operating profit (loss)	753,000	(1,515,000)
Assets	25,132,000		21,833,000
Operating Segments [Member] | Tubular [Member]
Net Sales	5,073,000	3,395,000
Operating profit (loss)	(1,000)	(274,000)
Assets	37,592,000		37,299,000
Corporate, Non-Segment [Member]
Corporate expenses	527,000	$ 557,000
Assets	$ 6,279,000		$ 4,131,000