v3.26.1
Schedule of Intangible Assets, Including Impact of Impairment Charges (Detail) - USD ($)
$ in Thousands
 12 Months Ended
Mar. 31, 2026
Mar. 31, 2025
Finite Lived Intangible Assets [Line Items]    
Intangible Assets, Cost $ 700,557 $ 582,523
Intangible Assets, Accumulated Amortization (115,083) (104,805)
Goodwill, Cost 469,894 392,569
Goodwill, Additions 779  
Goodwill, Net 470,673 469,894
Goodwill and Intangible Assets, Additions (31) 118,034
Goodwill and Intangible Assets, net $ 585,443 595,752
Goodwill [Member]    
Finite Lived Intangible Assets [Line Items]    
Goodwill, Additions   $ 77,325
Customer Contracts And Relationships [Member]    
Finite Lived Intangible Assets [Line Items]    
Intangible Assets, Useful Life 15 years 15 years
Intangible Assets, Cost $ 197,503 $ 157,294
Intangible Assets, Adjustments/Additions   40,209
Intangible Assets, Accumulated Amortization (98,712) (89,444)
Intangible Assets, Net 97,981 108,059
Goodwill, Additions (810)  
Permits [Member]    
Finite Lived Intangible Assets [Line Items]    
Intangible Assets, Cost 30,760 30,760
Intangible Assets, Adjustments/Additions   0
Intangible Assets, Accumulated Amortization (15,215) (14,358)
Intangible Assets, Net 15,545 $ 16,402
Goodwill, Additions $ 0  
Permits [Member] | Minimum [Member]    
Finite Lived Intangible Assets [Line Items]    
Intangible Assets, Useful Life 25 years 25 years
Permits [Member] | Maximum [Member]    
Finite Lived Intangible Assets [Line Items]    
Intangible Assets, Useful Life 40 years 40 years
Trade Name [Member]    
Finite Lived Intangible Assets [Line Items]    
Intangible Assets, Useful Life 15 years 15 years
Intangible Assets, Cost $ 2,400 $ 1,900
Intangible Assets, Adjustments/Additions   500
Intangible Assets, Accumulated Amortization (1,156) (1,003)
Intangible Assets, Net 1,244 $ 1,397
Goodwill, Additions $ 0