v3.26.3
Business Segment Information - Schedule of Revenue from Reportable Segments by Product Type (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]        
Net Sales $ 889,406 $ 850,381 $ 1,890,518 $ 1,680,261
Cost of goods sold 543,551 510,249 1,136,616 1,009,691
Selling, general and administrative expenses 116,942 107,840 235,273 199,966
Other segment items (70,580) (66,624) (151,621) (118,314)
Corporate and other costs 12,675 11,384 25,162 23,219
Consolidated Adjusted EBITDA 286,818 287,532 645,088 565,699
Interest expense 27,515 23,116 54,555 46,145
Interest income (1,407) (7,340) (2,698) (12,745)
Depreciation and amortization 63,685 54,693 125,842 104,921
Stock-based compensation expense 11,257 8,577 24,531 16,981
Loss (gain) on disposal of assets and costs from exit and disposal activities 1,302 (15,926) 3,923 (8,902)
Transaction costs 6,383 9,317 9,627 10,124
Inventory step up related to NDS acquisition     14,197 0
Other adjustments 1,587 6,904 9,655 11,562
Income before income taxes 176,496 208,191 405,456 397,613
Income tax expense 44,206 52,399 97,895 99,073
Equity in net income of unconsolidated affiliates (1,333) (708) (2,630) (2,051)
Net income from continuing operations 133,623 156,500 310,191 300,591
Intersegment Eliminations        
Segment Reporting [Line Items]        
Net Sales (31,266) (25,998) (60,016) (51,683)
Cost of goods sold (28,838) (26,110) (59,185) (51,038)
Segment Adjusted EBITDA (2,428) 112 (831) (645)
Stormwater        
Segment Reporting [Line Items]        
Net Sales 712,063 670,665 1,521,439 1,322,192
Stormwater | Operating Segments        
Segment Reporting [Line Items]        
Net Sales 723,097 680,011 1,544,039 1,340,614
Cost of goods sold 471,745 435,834 990,557 862,953
Selling, general and administrative expenses 100,386 88,979 201,067 162,761
Other segment items (62,256) (55,420) (134,508) (99,213)
Segment Adjusted EBITDA 213,222 210,618 486,923 414,113
Depreciation and amortization 41,649 29,625 82,153 58,521
Stormwater | Intersegment Eliminations        
Segment Reporting [Line Items]        
Net Sales 11,034 9,346 22,600 18,422
Wastewater        
Segment Reporting [Line Items]        
Net Sales 177,343 179,716 369,079 358,069
Wastewater | Operating Segments        
Segment Reporting [Line Items]        
Net Sales 197,575 196,368 406,495 391,330
Cost of goods sold 100,644 100,525 205,244 197,776
Selling, general and administrative expenses 16,556 18,861 34,206 37,205
Other segment items (8,324) (11,204) (17,113) (19,101)
Segment Adjusted EBITDA 88,699 88,186 184,158 175,450
Depreciation and amortization 18,888 22,875 37,755 42,129
Wastewater | Intersegment Eliminations        
Segment Reporting [Line Items]        
Net Sales $ 20,232 $ 16,652 $ 37,416 $ 33,261