Note K - Revenue (Details Textual)	3 Months Ended		6 Months Ended
	Sep. 30, 2020 USD ($)	Sep. 30, 2019 USD ($)	Sep. 30, 2020 USD ($)	Sep. 30, 2019 USD ($)
Number of Reportable Segments			2
Revenue from Contract with Customer, Including Assessed Tax	$ 24,861,680	$ 39,995,580	$ 48,386,280	$ 80,970,900
Pipe Finishing Services [Member]
Revenue from Contract with Customer, Including Assessed Tax	$ 0	$ 0	$ 0	$ 0