Goodwill - Changes in Goodwill (Detail) $ in Millions	3 Months Ended
	Mar. 31, 2022 USD ($)
Goodwill [Line Items]
Balance at January 1, 2022	$ 3,494.4
Adjustments to purchase price allocations	8.8
Goodwill allocated to assets held for sale	(111.2)
Balance at March 31, 2022	3,392.0
East Group
Goodwill [Line Items]
Balance at January 1, 2022	759.4
Adjustments to purchase price allocations	5.0
Balance at March 31, 2022	764.4
West Group
Goodwill [Line Items]
Balance at January 1, 2022	2,735.0
Adjustments to purchase price allocations	3.8
Goodwill allocated to assets held for sale	(111.2)
Balance at March 31, 2022	$ 2,627.6