Business Segments Information - Schedule of Revenue from Reportable Segments by Product Type (Detail) - USD ($) $ in Thousands	3 Months Ended
	Jun. 30, 2016	Jun. 30, 2015
Segment Reporting Information [Line Items]
Total Net sales	$ 357,576	$ 349,124
Domestic [Member]
Segment Reporting Information [Line Items]
Total Net sales	312,763	298,164
Domestic [Member] | Pipe [Member]
Segment Reporting Information [Line Items]
Total Net sales	223,310	220,533
Domestic [Member] | Allied Products [Member]
Segment Reporting Information [Line Items]
Total Net sales	89,453	77,631
International Segment [Member]
Segment Reporting Information [Line Items]
Total Net sales	44,813	50,960
International Segment [Member] | Pipe [Member]
Segment Reporting Information [Line Items]
Total Net sales	34,372	42,376
International Segment [Member] | Allied Products [Member]
Segment Reporting Information [Line Items]
Total Net sales	$ 10,441	$ 8,584