Condensed Consolidated Statements of Comprehensive Income - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Statement of Comprehensive Income [Abstract]
Net income	$ 7.4	$ 10.5	$ 8.0	$ 12.3
Other comprehensive expense	(0.2)	(0.1)	(0.3)	(0.6)
Comprehensive income	7.2	10.4	7.7	11.7
Less: Comprehensive income attributable to noncontrolling interest	0.9	0.7	1.5	1.2
Comprehensive income attributable to SP Plus Corporation	$ 6.3	$ 9.7	$ 6.2	$ 10.5