v3.26.1
Acquisitions - Summary of Consideration Transferred and Preliminary Purchase Price Allocation of Assets Acquired and Liabilities Assumed (Detail) - USD ($)
$ in Thousands
 5 Months Ended 6 Months Ended 12 Months Ended
Sep. 30, 2025
Mar. 31, 2025
Mar. 31, 2026
Feb. 02, 2026
May 08, 2025
Oct. 01, 2024
Mar. 31, 2024
Business Combination [Line Items]              
Cash   $ 463,319 $ 223,012       $ 490,163
Goodwill   720,223 1,042,716       $ 617,183
Orenco Systems, Inc.              
Business Combination [Line Items]              
Accounts receivable     12,117     $ 12,277  
Accounts receivable, Purchase Accounting Adjustments   (160)          
Inventory     15,651     15,651  
Other current assets     219     219  
Property, plant and equipment, Purchase Accounting Adjustments   (1,228)          
Property, plant and equipment     7,305     8,533  
Goodwill     104,231     104,007  
Goodwill, Purchase Accounting Adjustments   224          
Intangible assets     148,000     148,000  
Other assets     9,041     9,041  
BusinessCombinationPurchaseAccountingAdjustmentsAssets   (1,164)          
Business Combination, Recognized Asset Acquired, Asset     296,564     297,728  
Accounts payable     (3,618)     (3,618)  
Accrued expenses     (15,823)     (15,823)  
Other liabilities     (4,727)     (4,727)  
Business Combination, Recognized Liability Assumed, Deferred Tax Liability     (36,103)     (36,250)  
Deferred tax liabilities, Purchase Accounting Adjustments   147          
Total liabilities acquired   (147)          
Total liabilities acquired     (60,271)     (60,418)  
Business Combination, Recognized Asset Acquired to Liability Assumed, Excess (Less), and Goodwill, Total     (236,293)     $ (237,310)  
Consideration transferred, valuation adjustments   $ (1,017)          
River Valley Pipe              
Business Combination [Line Items]              
Accounts receivable     3,101   $ 3,101    
Inventory     3,027   3,027    
Property, plant and equipment     6,986   6,986    
Goodwill     3,935   4,964    
Goodwill, Purchase Accounting Adjustments $ (1,029)            
Intangible assets     2,970   2,970    
Other assets     75   75    
BusinessCombinationPurchaseAccountingAdjustmentsAssets (1,029)            
Business Combination, Recognized Asset Acquired, Asset     20,094   21,123    
Accounts payable     (1,227)   (1,227)    
Accrued expenses     (49)   (285)    
Other liabilities     (35)   (35)    
Deferred tax liabilities, Purchase Accounting Adjustments     (236)        
Total liabilities acquired     (236)        
Total liabilities acquired     (1,311)   (1,547)    
Business Combination, Recognized Asset Acquired to Liability Assumed, Excess (Less), and Goodwill, Total     (18,783)   $ (19,576)    
Consideration transferred, valuation adjustments $ 793            
National Diversified Sales              
Business Combination [Line Items]              
Cash     3,189        
Accounts receivable       $ 44,944      
Inventory       93,092      
Other current assets       1,359      
AssetsHeldForSaleAcquired       42,554      
Property, plant and equipment       67,699      
Goodwill       317,677      
Intangible assets       456,920      
Business Combination, Recognized Asset Acquired, Deferred Tax Asset       5,751      
Other assets       17,212      
Business Combination, Recognized Asset Acquired, Asset       1,050,397      
Accounts payable       (10,664)      
Accrued expenses       (29,285)      
Liabilities held for sale       (13,779)      
Other liabilities       (11,788)      
Total liabilities acquired       (65,516)      
Business Combination, Recognized Asset Acquired to Liability Assumed, Excess (Less), and Goodwill, Total     $ (972,500) $ (984,881)