Business Segment Information - Schedule of Financial Information Attributable to Reportable Segments (Detail) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Mar. 31, 2019
Segment Reporting Information [Line Items]
Segment adjusted gross profit	$ 788,479	$ 574,086	$ 396,922
Depreciation and amortization	145,586	124,940	71,900
Capital expenditures	78,757	67,677	43,412
Operating Segments [Member] | Pipe Segment [Member]
Segment Reporting Information [Line Items]
Segment adjusted gross profit	322,846	239,531	191,002
Depreciation and amortization	46,078	46,611	49,419
Capital expenditures	17,135	33,629	34,878
Operating Segments [Member] | Infiltrator Segment [Member]
Segment Reporting Information [Line Items]
Segment adjusted gross profit	191,163	98,245
Depreciation and amortization	12,468	7,159
Capital expenditures	54,024	24,917
Operating Segments [Member] | International Segment [Member]
Segment Reporting Information [Line Items]
Segment adjusted gross profit	49,921	36,999	37,191
Depreciation and amortization	5,430	6,013	5,938
Capital expenditures	1,627	2,623	3,765
Operating Segments [Member] | Allied Products and Other [Member]
Segment Reporting Information [Line Items]
Segment adjusted gross profit	225,052	201,206	168,729
Depreciation and amortization	81,610	65,157	16,543
Capital expenditures	5,971	6,508	$ 4,769
Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Segment adjusted gross profit	$ (503)	$ (1,895)