Schedule of Intangible Assets, Including Impact of Impairment Charges (Detail) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Finite Lived Intangible Assets [Line Items]
Intangible Assets, Cost	$ 469,657	$ 469,657
Intangible Assets, Accumulated Amortization	(81,759)	(77,342)
Goodwill, Cost	329,137	329,137
Goodwill, Additions	0
Goodwill, Net	329,137	329,137
Goodwill and Intangible Assets, Additions	0
Goodwill and Intangible Assets, net	387,898	392,315
Goodwill, Net	$ 329,137	$ 329,137
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	$ 108,610	$ 108,610
Intangible Assets, Additions	0
Intangible Assets, Accumulated Amortization	(69,866)	(66,445)
Intangible Assets, Net	38,744	42,165
Permits [Member]
Finite Lived Intangible Assets [Line Items]
Intangible Assets, Cost	30,410	30,410
Intangible Assets, Additions	0
Intangible Assets, Accumulated Amortization	(11,629)	(10,759)
Intangible Assets, Net	$ 18,781	$ 19,651
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	$ 1,500	$ 1,500
Intangible Assets, Additions	0
Intangible Assets, Accumulated Amortization	(264)	(138)
Intangible Assets, Net	$ 1,236	$ 1,362