CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Statement Of Income And Comprehensive Income [Abstract]
Net loss	$ (4.1)	$ (30.2)	$ (24.0)	$ (67.8)
Other comprehensive income (loss):
Currency translation adjustments	10.3	(2.4)	(28.8)	6.1
Amortization of cash flow hedge into income, net of tax expense ($0.1 and $0.2) for the three and six months ended June 30, 2019, respectively		0.2		0.4
Change in fair value of cash flow hedge, net of tax expense ($0.1 for both the three and six months ended June 30, 2019)		0.2		0.2
Reclassification of cash flow hedge, net of tax expense ($1.1 for both the three and six months ended June 30, 2019)		2.3		2.3
Total other comprehensive income (loss)	10.3	0.3	(28.8)	9.0
Comprehensive income (loss)	6.2	(29.9)	(52.8)	(58.8)
Less: comprehensive income attributable to noncontrolling interests	0.4	0.3	0.7	0.8
Comprehensive income (loss) attributable to Stericycle, Inc. common shareholders	$ 5.8	$ (30.2)	$ (53.5)	$ (59.6)