CONDENSED CONSOLIDATED STATEMENTS OF (LOSS) INCOME - USD ($) shares in Millions, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Income Statement [Abstract]
Revenues	$ 648.9	$ 636.4	$ 1,989.6	$ 2,019.6
Cost of revenues	409.2	369.1	1,219.4	1,236.0
Gross profit	239.7	267.3	770.2	783.6
Selling, general and administrative expenses	279.4	219.0	695.2	678.7
Divestiture losses (gains), net	10.9	104.1	10.9	166.2
(Loss) income from operations	(50.6)	(55.8)	64.1	(61.3)
Interest expense, net	(18.8)	(17.7)	(55.1)	(62.0)
Other income (expense), net	0.5	(0.9)	0.5	(4.8)
(Loss) income before income taxes	(68.9)	(74.4)	9.5	(128.1)
Income tax benefit (expense)	3.0	(6.5)	(19.9)	23.2
Net (loss) income	(65.9)	(80.9)	(10.4)	(104.9)
Net income attributable to noncontrolling interests	(0.1)	(0.3)	(0.2)	(0.9)
Net (loss) income attributable to Stericycle, Inc. common shareholders	$ (66.0)	$ (81.2)	$ (10.6)	$ (105.8)
(Loss) earnings per common share attributable to Stericycle, Inc. common shareholders:
Basic (in dollars per share)	$ (0.72)	$ (0.89)	$ (0.11)	$ (1.16)
Diluted (in dollars per share)	$ (0.72)	$ (0.89)	$ (0.11)	$ (1.16)
Weighted average number of common shares outstanding:
Basic (in shares)	91.9	91.5	91.8	91.4
Diluted (in shares)	91.9	91.5	91.8	91.4