Net Sales - Summary of Net Sales by Product Line and Geography (Details) - USD ($) $ in Millions	3 Months Ended						6 Months Ended
	Jun. 30, 2022	Mar. 31, 2022	Dec. 31, 2021	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Jun. 30, 2022	Jun. 30, 2021
Disaggregation Of Revenue [Line Items]
Net sales	$ 2,358.2	$ 1,686.9	$ 1,754.9	$ 1,875.4	$ 1,872.1	$ 1,318.0	$ 4,045.1	$ 3,190.1
Residential roofing products
Disaggregation Of Revenue [Line Items]
Net sales	1,196.1				981.6		2,042.6	1,676.7
Non-residential roofing products
Disaggregation Of Revenue [Line Items]
Net sales	682.6				486.7		1,170.3	816.5
Complementary building products
Disaggregation Of Revenue [Line Items]
Net sales	479.5				403.8		832.2	696.9
U.S.
Disaggregation Of Revenue [Line Items]
Net sales	2,279.5				1,802.8		3,923.5	3,086.5
U.S. | Residential roofing products
Disaggregation Of Revenue [Line Items]
Net sales	1,168.6				955.9		2,004.4	1,642.1
U.S. | Non-residential roofing products
Disaggregation Of Revenue [Line Items]
Net sales	634.8				446.4		1,092.2	752.4
U.S. | Complementary building products
Disaggregation Of Revenue [Line Items]
Net sales	476.1				400.5		826.9	692.0
Canada
Disaggregation Of Revenue [Line Items]
Net sales	78.7				69.3		121.6	103.6
Canada | Residential roofing products
Disaggregation Of Revenue [Line Items]
Net sales	27.5				25.7		38.2	34.6
Canada | Non-residential roofing products
Disaggregation Of Revenue [Line Items]
Net sales	47.8				40.3		78.1	64.1
Canada | Complementary building products
Disaggregation Of Revenue [Line Items]
Net sales	$ 3.4				$ 3.3		$ 5.3	$ 4.9