Condensed Consolidated Statements of Comprehensive Income - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Statement of Comprehensive Income [Abstract]
Net (loss) income	$ (45.6)	$ 10.9
Effective portion of unrealized loss on cash flow hedge	(2.8)	0.0
Foreign currency translation	(0.2)	0.2
Comprehensive (loss) income	(48.6)	11.1
Less: Comprehensive income attributable to noncontrolling interest	0.5	0.3
Comprehensive (loss) income attributable to SP Plus Corporation	$ (49.1)	$ 10.8