CONDENSED CONSOLIDATED STATEMENTS OF INCOME (LOSS) - USD ($) shares in Millions, $ in Millions	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Income Statement [Abstract]
Revenues	$ 668.0	$ 785.0
Cost of revenues	406.6	498.4
Gross profit	261.4	286.6
Selling, general and administrative expenses	202.3	258.7
Divestiture losses (gains), net	0.0	58.3
Income (loss) from operations	59.1	(30.4)
Interest expense, net	(18.4)	(25.0)
Other expense, net	(0.7)	(2.9)
Income (loss) before income taxes	40.0	(58.3)
Income tax (expense) benefit	(13.8)	38.4
Net income (loss)	26.2	(19.9)
Net income attributable to noncontrolling interests	(0.1)	(0.2)
Net income (loss) attributable to Stericycle, Inc. common shareholders	$ 26.1	$ (20.1)
Earnings (loss) per common share attributable to Stericycle, Inc. common shareholders:
Basic (in dollars per share)	$ 0.29	$ (0.22)
Diluted (in dollars per share)	$ 0.28	$ (0.22)
Weighted average number of common shares outstanding:
Basic (in shares)	91.6	91.3
Diluted (in shares)	92.0	91.3