Information on Business Segments - Net Sales and Operating Income by Segment (Detail) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Net sales	$ 1,986.3	$ 1,652.1	$ 5,693.4	$ 4,430.6
Operating income	$ 286.6	240.2	$ 829.9	568.2
Net Sales, Percentage Change vs. Prior Year	20.20%		28.50%
Operating Income, Percentage Change vs. Prior Year	19.30%		46.10%
Corporate [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Operating income	$ (27.5)	(25.3)	$ (79.3)	(69.0)
Operating Income, Percentage Change vs. Prior Year	(8.70%)		(14.90%)
Plumbing [Member] \| Operating Segments [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Net sales	$ 741.4	590.6	$ 2,057.6	1,564.4
Operating income	$ 166.5	116.6	$ 483.3	330.6
Net Sales, Percentage Change vs. Prior Year	25.50%		31.50%
Operating Income, Percentage Change vs. Prior Year	42.80%		46.20%
Outdoors & Security [Member] \| Operating Segments [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Net sales	$ 528.4	406.7	$ 1,525.4	1,052.7
Operating income	$ 80.4	66.8	$ 211.7	143.5
Net Sales, Percentage Change vs. Prior Year	29.90%		44.90%
Operating Income, Percentage Change vs. Prior Year	20.40%		47.50%
Cabinets [Member] \| Operating Segments [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Net sales	$ 716.5	654.8	$ 2,110.4	1,813.5
Operating income	$ 67.2	$ 82.1	$ 214.2	$ 163.1
Net Sales, Percentage Change vs. Prior Year	9.40%		16.40%
Operating Income, Percentage Change vs. Prior Year	(18.10%)		31.30%