Condensed Consolidated Statements of Operations - USD ($) shares in Millions, $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Income Statement [Abstract]
Net sales	$ 2,211.2	$ 2,160.0
Cost of goods sold (exclusive of depreciation)	1,678.6	1,663.6
Operating expenses:
Outbound freight and handling	91.5	82.9
Warehousing, selling and administrative	279.5	253.4
Other operating expenses, net	4.1	164.8
Depreciation	41.7	33.2
Amortization	15.8	14.4
Total operating expenses	432.6	548.7
Operating income (loss)	100.0	(52.3)
Other (expense) income:
Interest income	1.0	0.6
Interest expense	(29.1)	(34.8)
Loss on sale of business	(8.6)	0.0
Loss on extinguishment of debt	(1.8)	(0.7)
Other expense, net	(5.9)	(6.1)
Total other expense	(44.4)	(41.0)
Income (loss) before income taxes	55.6	(93.3)
Income tax benefit	(0.3)	(23.3)
Net income (loss) from continuing operations	55.9	(70.0)
Net income from discontinued operations	0.0	6.1
Net income (loss)	$ 55.9	$ (63.9)
Income (loss) per common share:
Basic from continuing operations (in dollars per share)	$ 0.33	$ (0.47)
Basic from discontinued operations (in dollars per share)	0	0.04
Basic income (loss) per common share (in dollars per share)	0.33	(0.43)
Diluted from continuing operations (in dollars per share)	0.33	(0.47)
Diluted from discontinued operations (in dollars per share)	0	0.04
Diluted income (loss) per common share (in dollars per share)	$ 0.33	$ (0.43)
Weighted average common shares outstanding:
Basic (in shares)	168.8	149.2
Diluted (in shares)	169.7	149.2