CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Statement Of Income And Comprehensive Income [Abstract]
Net income	$ 22.5	$ 58.6
Other comprehensive income:
Foreign currency translation adjustments	16.3	26.5
Amortization of cash flow hedge into income, net of tax expense ($0.1 and $0.2 for the three months ended March 31, 2018 and 2017, respectively)	(0.1)	(0.3)
Total other comprehensive income	16.4	26.8
Comprehensive income	38.9	85.4
Less: comprehensive income attributable to noncontrolling interests	0.1	0.7
Comprehensive income attributable to Stericycle, Inc. common shareholders	$ 38.8	$ 84.7