Segment Information - Segment Information (Detail) - USD ($)	3 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Mar. 31, 2015
Segment Reporting Information [Line Items]
Net sales	$ 23,968,569	$ 27,904,521
Interest & other income	(17,250)	(15,252)
Earnings (loss) before income taxes	805,687	(77,263)
Total assets	66,893,687		$ 66,958,024
Operating Segments
Segment Reporting Information [Line Items]
Operating profit (loss)	1,518,000	368,000
Total assets	61,751,000		63,393,000
Operating Segments | Coil
Segment Reporting Information [Line Items]
Net sales	19,348,000	17,906,000
Operating profit (loss)	2,155,000	(404,000)
Total assets	22,608,000		21,249,000
Operating Segments | Tubular
Segment Reporting Information [Line Items]
Net sales	4,621,000	9,999,000
Operating profit (loss)	(637,000)	772,000
Total assets	39,143,000		42,144,000
Corporate and other
Segment Reporting Information [Line Items]
Corporate expenses	729,000	$ 460,000
Total assets	$ 5,143,000		$ 3,565,000