v3.26.3
Business Segment Information - Schedule of Financial Information Attributable to Reportable Segments (Detail) - USD ($)
$ in Thousands
 3 Months Ended 6 Months Ended
Sep. 30, 2026
Sep. 30, 2025
Sep. 30, 2026
Sep. 30, 2025
Segment Reporting [Line Items]        
Depreciation and amortization $ 63,685 $ 54,693 $ 125,842 $ 104,921
Capital Expenditures 41,607 58,420 98,758 111,018
Operating Segments | Stormwater        
Segment Reporting [Line Items]        
Depreciation and amortization 41,649 29,625 82,153 58,521
Capital Expenditures 35,792 38,541 78,296 79,143
Operating Segments | Wastewater        
Segment Reporting [Line Items]        
Depreciation and amortization 18,888 22,875 37,755 42,129
Capital Expenditures 4,865 11,994 19,221 17,729
Operating Segments | Other        
Segment Reporting [Line Items]        
Depreciation and amortization 3,148 2,193 5,934 4,271
Capital Expenditures $ 950 $ 7,885 $ 1,241 $ 14,146