Schedule of Intangible Assets, Including Impact of Impairment Charges (Detail) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Finite Lived Intangible Assets [Line Items]
Intangible Assets, Cost	$ 554,565	$ 469,657
Intangible Assets, Accumulated Amortization	(96,406)	(88,522)
Goodwill, Cost	380,711	329,137
Goodwill, Additions	11,858	51,574
Goodwill, Net	392,569	380,711
Goodwill and Intangible Assets, Additions	27,958	84,908
Goodwill and Intangible Assets, net	486,117	466,043
Goodwill, Net	$ 392,569	$ 380,711
Minimum [Member]
Finite Lived Intangible Assets [Line Items]
Intangible Assets, Useful Life		25 years
Maximum [Member]
Finite Lived Intangible Assets [Line Items]
Intangible Assets, Useful Life		40 years
Customer Contracts And Relationships [Member]
Finite Lived Intangible Assets [Line Items]
Intangible Assets, Useful Life	15 years	15 years
Intangible Assets, Cost	$ 141,194	$ 108,610
Intangible Assets, Additions	16,100	32,584
Intangible Assets, Accumulated Amortization	(82,077)	(75,413)
Intangible Assets, Net	75,217	65,781
Permits [Member]
Finite Lived Intangible Assets [Line Items]
Intangible Assets, Cost	30,760	30,410
Intangible Assets, Additions		350
Intangible Assets, Accumulated Amortization	(13,413)	(12,519)
Intangible Assets, Net	$ 17,347	$ 18,241
Permits [Member] | Minimum [Member]
Finite Lived Intangible Assets [Line Items]
Intangible Assets, Useful Life	25 years
Permits [Member] | Maximum [Member]
Finite Lived Intangible Assets [Line Items]
Intangible Assets, Useful Life	40 years
Trade Name [Member]
Finite Lived Intangible Assets [Line Items]
Intangible Assets, Useful Life	15 years	15 years
Intangible Assets, Cost	$ 1,900	$ 1,500
Intangible Assets, Additions		400
Intangible Assets, Accumulated Amortization	(916)	(590)
Intangible Assets, Net	$ 984	$ 1,310