v3.26.1
Business Segment Information - Schedule of Revenue from Reportable Segments by Product Type (Detail) - USD ($)
$ in Thousands
 12 Months Ended
Mar. 31, 2026
Mar. 31, 2025
Mar. 31, 2024
Segment Reporting Information [Line Items]      
Net sales $ 3,050,376 $ 2,904,245 $ 2,874,473
Cost of goods sold 1,882,990 1,810,004 1,728,524
Selling, general and administrative 417,831 338,063 315,981
Other segment items (265,069) (175,365) (147,712)
Total consolidated Adjusted EBITDA 962,906 889,228 922,947
Interest expense 93,869 91,803 88,862
Interest income (25,000) (23,485) (22,047)
Depreciation and amortization 216,261 183,281 154,903
Stock-based compensation 32,354 26,581 31,986
Loss (gain) on disposal of assets and costs from exit and disposal activities 19,211 3,858 (8,365)
Transaction costs 40,805 9,291 3,444
Other adjustments 25,618 8,434 7,411
Income before income taxes 559,788 589,465 666,753
Income tax expense 134,988 141,063 158,998
Equity in net income of unconsolidated affiliates (5,063) (4,171) (5,536)
Net income from continuing operations 429,863 452,573 513,291
Stormwater      
Segment Reporting Information [Line Items]      
Net sales 2,397,414 2,326,370 2,361,520
Wastewater      
Segment Reporting Information [Line Items]      
Net sales 652,962 577,875 512,953
Intersegment Eliminations      
Segment Reporting Information [Line Items]      
Net sales (98,046) (87,678) (84,246)
Cost of goods sold (98,143) (87,289) (81,042)
Segment Adjusted EBITDA 97 (389) (3,204)
Intersegment Eliminations | Stormwater      
Segment Reporting Information [Line Items]      
Net sales 36,466 35,647 30,649
Intersegment Eliminations | Wastewater      
Segment Reporting Information [Line Items]      
Net sales 61,580 52,031 53,597
Operating Segments | Stormwater      
Segment Reporting Information [Line Items]      
Net sales 2,433,880 2,362,017 2,392,169
Cost of goods sold 1,613,170 1,582,828 1,525,826
Selling, general and administrative 348,829 282,877 275,342
Other segment items (231,194) (143,608) (122,966)
Segment Adjusted EBITDA 703,075 639,920 713,967
Depreciation and amortization 126,387 102,574 81,602
Operating Segments | Wastewater      
Segment Reporting Information [Line Items]      
Net sales 714,542 629,906 566,550
Cost of goods sold 367,963 314,465 283,740
Selling, general and administrative 69,002 55,186 40,639
Other segment items (33,875) (31,757) (24,746)
Segment Adjusted EBITDA 311,452 292,012 266,917
Depreciation and amortization $ 80,423 $ 74,068 $ 69,121