CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Statement of Comprehensive Income [Abstract]
Net loss	$ (80.9)	$ (59.0)	$ (104.9)	$ (126.8)
Other comprehensive income (loss):
Currency translation adjustment	30.3	(28.9)	1.5	(22.8)
Cumulative currency translation loss realized through disposition of Argentina operations	87.2	0.0	87.2	0.0
Amortization of cash flow hedge into income, net of tax expense ($0.0 and $0.2 for the three and nine months ended September 30, 2019)	0.0	0.0	0.0	0.4
Change in fair value of cash flow hedge, net of tax expense ($0.1 for the nine months ended September 30, 2019)	0.0	0.0	0.0	0.2
Reclassification of cash flow hedge, net of tax expense ($1.1 for the nine months ended September 30, 2019)	0.0	0.0	0.0	2.3
Total other comprehensive income (loss)	117.5	(28.9)	88.7	(19.9)
Comprehensive income (loss)	36.6	(87.9)	(16.2)	(146.7)
Less: comprehensive income attributable to noncontrolling interests	0.4	0.1	1.1	0.9
Comprehensive income (loss) attributable to Stericycle, Inc. common shareholders	$ 36.2	$ (88.0)	$ (17.3)	$ (147.6)