Information on Business Segments - Net Sales and Operating Income by Segment (Detail) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Net sales	$ 1,652.1	$ 1,459.0	$ 4,430.6	$ 4,294.1
Operating income	$ 240.2	168.0	$ 568.2	506.0
Net Sales, Percentage Change vs. Prior Year	13.20%		3.20%
Operating Income, Percentage Change vs. Prior Year	43.00%		12.30%
Corporate [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Operating income	$ (25.3)	(19.2)	$ (69.0)	(58.4)
Operating Income, Percentage Change vs. Prior Year	(31.80%)		(18.20%)
Plumbing [Member] \| Operating Segments [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Net sales	$ 590.6	514.1	$ 1,564.4	1,478.8
Operating income	$ 116.6	112.0	$ 330.6	307.9
Net Sales, Percentage Change vs. Prior Year	14.90%		5.80%
Operating Income, Percentage Change vs. Prior Year	4.10%		7.40%
Doors & Security [Member] \| Operating Segments [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Net sales	$ 406.7	355.2	$ 1,052.7	1,017.6
Operating income	$ 66.8	50.1	$ 143.5	122.5
Net Sales, Percentage Change vs. Prior Year	14.50%		3.40%
Operating Income, Percentage Change vs. Prior Year	33.30%		17.10%
Cabinets [Member] \| Operating Segments [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Net sales	$ 654.8	589.7	$ 1,813.5	1,797.7
Operating income	$ 82.1	$ 25.1	$ 163.1	$ 134.0
Net Sales, Percentage Change vs. Prior Year	11.00%		0.90%
Operating Income, Percentage Change vs. Prior Year	227.10%		21.70%