CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Statement Of Income And Comprehensive Income [Abstract]
Net income	$ 43.0	$ 207.9	$ 268.0
Other comprehensive income (loss):
Foreign currency translation adjustments	80.5	(86.7)	(140.6)
Amortization of cash flow hedge into income, net of tax expense ($0.7, $0.8, and $0.4 for the years ended December 31, 2017, 2016, and 2015, respectively)	1.0	1.1	0.7
Change in fair value of cash flow hedge, net of tax expense (benefit) ($0.0, $0.0, and ($2.6)) for the years ended December 31, 2017, 2016, and 2015, respectively)	0.3	0.2	(4.1)
Total other comprehensive income (loss)	81.8	(85.4)	(144.0)
Comprehensive income	124.8	122.5	124.0
Less: comprehensive income attributable to noncontrolling interests	1.8	1.2	1.2
Comprehensive income attributable to Stericycle, Inc. common shareholders	$ 123.0	$ 121.3	$ 122.8