Segment and Geographic Information - Geographic Reporting Segments (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Segment Reporting Information [Line Items]
Net sales	$ 4,252.1	$ 4,502.6	$ 4,263.9	$ 3,939.3	$ 4,154.8	$ 4,422.6	$ 4,339.0	$ 3,754.1	$ 16,957.9	$ 16,670.5	$ 16,395.3
Income (loss) before income taxes	22.4	32.2	22.6	6.1	20.8	30.6	24.2	1.8	83.3	77.4	59.9
Interest expense, net	2.1	2.1	2.8	3.5	3.6	4.2	3.2	3.4	10.5	14.4	13.7
Depreciation and amortization	17.7	16.5	16.7	15.7	15.1	14.9	15.5	15.4	66.6	60.9	59.5
Capital expenditures	$ 9.3	$ 8.1	$ 4.8	$ 5.0	$ 7.5	$ 6.1	$ 4.1	$ 5.1	27.2	22.8	20.1
Interest income									0.3	0.5	0.3
Corporate, Non-Segment
Segment Reporting Information [Line Items]
Net sales									43.9	53.7	56.9
Income (loss) before income taxes									(46.0)	(33.7)	(37.7)
Interest expense, net									(48.9)	(43.7)	(42.0)
Depreciation and amortization									17.2	15.7	15.1
United States | Reportable Geographical Components
Segment Reporting Information [Line Items]
Net sales									15,352.3	15,113.7	14,844.4
Income (loss) before income taxes									116.7	99.2	89.7
Interest expense, net									58.7	56.6	54.7
Depreciation and amortization									45.9	42.6	42.1
Capital expenditures									25.6	20.3	18.6
Canada | Reportable Geographical Components
Segment Reporting Information [Line Items]
Net sales									1,561.7	1,503.1	1,494.0
Income (loss) before income taxes									12.6	11.9	7.9
Interest expense, net									0.7	1.5	1.0
Depreciation and amortization									3.5	2.6	2.3
Capital expenditures									$ 1.6	$ 2.5	$ 1.5