Goodwill and Other Intangible Assets - Goodwill and Accumulated Goodwill Impairment Losses (Details) - USD ($)	3 Months Ended		6 Months Ended
	Mar. 31, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Goodwill [Roll Forward]
Goodwill, gross, beginning balance	$ 2,640,500,000		$ 2,640,500,000
Accumulated goodwill impairment losses, beginning balance	(1,369,800,000)		(1,369,800,000)
Goodwill, net, beginning balance	1,270,700,000		1,270,700,000
Goodwill, impairment loss during period	(113,000,000.0)	$ 0	(113,000,000.0)	$ 0
Goodwill, gross, ending balance			2,640,500,000
Accumulated goodwill impairment losses, ending balance			(1,482,800,000)
Goodwill, net, ending balance			1,157,700,000
Operating segments | Northeast segment
Goodwill [Roll Forward]
Goodwill, gross, beginning balance	914,300,000		914,300,000
Accumulated goodwill impairment losses, beginning balance	(717,900,000)		(717,900,000)
Goodwill, net, beginning balance	196,400,000		196,400,000
Goodwill, impairment loss during period	(43,500,000)		(43,500,000)
Goodwill, gross, ending balance			914,300,000
Accumulated goodwill impairment losses, ending balance			(761,400,000)
Goodwill, net, ending balance			152,900,000
Operating segments | South segment
Goodwill [Roll Forward]
Goodwill, gross, beginning balance	236,600,000		236,600,000
Accumulated goodwill impairment losses, beginning balance	(52,000,000.0)		(52,000,000.0)
Goodwill, net, beginning balance	184,600,000		184,600,000
Goodwill, impairment loss during period	(9,000,000.0)		(9,000,000.0)
Goodwill, gross, ending balance			236,600,000
Accumulated goodwill impairment losses, ending balance			(61,000,000.0)
Goodwill, net, ending balance			175,600,000
Operating segments | West segment
Goodwill [Roll Forward]
Goodwill, gross, beginning balance	216,800,000		216,800,000
Accumulated goodwill impairment losses, beginning balance	(16,600,000)		(16,600,000)
Goodwill, net, beginning balance	200,200,000		200,200,000
Goodwill, impairment loss during period			0
Goodwill, gross, ending balance			216,800,000
Accumulated goodwill impairment losses, ending balance			(16,600,000)
Goodwill, net, ending balance			200,200,000
Operating segments | Midwest segment
Goodwill [Roll Forward]
Goodwill, gross, beginning balance	1,116,700,000		1,116,700,000
Accumulated goodwill impairment losses, beginning balance	(495,600,000)		(495,600,000)
Goodwill, net, beginning balance	621,100,000		621,100,000
Goodwill, impairment loss during period	(60,500,000)		(60,500,000)
Goodwill, gross, ending balance			1,116,700,000
Accumulated goodwill impairment losses, ending balance			(556,100,000)
Goodwill, net, ending balance			560,600,000
Other
Goodwill [Roll Forward]
Goodwill, gross, beginning balance	156,100,000		156,100,000
Accumulated goodwill impairment losses, beginning balance	(87,700,000)		(87,700,000)
Goodwill, net, beginning balance	$ 68,400,000		68,400,000
Goodwill, impairment loss during period			0
Goodwill, gross, ending balance			156,100,000
Accumulated goodwill impairment losses, ending balance			(87,700,000)
Goodwill, net, ending balance			$ 68,400,000