CONDENSED CONSOLIDATED STATEMENTS OF INCOME (LOSS) - USD ($) shares in Millions, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Income Statement [Abstract]
Revenues	$ 672.7	$ 598.2	$ 1,340.7	$ 1,383.2
Cost of revenues	403.6	368.5	810.2	866.9
Gross profit	269.1	229.7	530.5	516.3
Selling, general and administrative expenses	213.5	201.0	415.8	459.7
Divestiture losses (gains), net	0.0	3.8	0.0	62.1
Income (loss) from operations	55.6	24.9	114.7	(5.5)
Interest expense, net	(17.9)	(19.3)	(36.3)	(44.3)
Other income (expense), net	0.7	(1.0)	0.0	(3.9)
Income (loss) before income taxes	38.4	4.6	78.4	(53.7)
Income tax (expense) benefit	(9.1)	(8.7)	(22.9)	29.7
Net income (loss)	29.3	(4.1)	55.5	(24.0)
Net income attributable to noncontrolling interests	0.0	(0.4)	(0.1)	(0.6)
Net income (loss) attributable to Stericycle, Inc. common shareholders	$ 29.3	$ (4.5)	$ 55.4	$ (24.6)
Earnings (loss) per common share attributable to Stericycle, Inc. common shareholders:
Basic (in dollars per share)	$ 0.32	$ (0.05)	$ 0.60	$ (0.27)
Diluted (in dollars per share)	$ 0.32	$ (0.05)	$ 0.60	$ (0.27)
Weighted average number of common shares outstanding:
Basic (in shares)	91.8	91.4	91.7	91.4
Diluted (in shares)	92.1	91.4	92.1	91.4