Condensed Consolidated Statements of Income - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Parking services revenue	$ 362.2	$ 403.5	$ 729.0	$ 805.4
Cost of parking services	311.1	346.0	638.4	707.4
Gross profit	51.1	57.5	90.6	98.0
General and administrative expenses	22.3	22.5	44.6	43.7
Depreciation and amortization	4.5	4.8	8.5	11.4
Operating income	24.3	30.2	37.5	42.9
Other expenses (income)
Interest expense	2.2	2.3	4.3	4.9
Interest income	(0.1)	(0.2)	(0.2)	(0.3)
Gain on sale of a business	0.0	(0.1)	0.0	(0.1)
Equity in (earnings) losses from investment in unconsolidated entity	0.0	0.2	(10.0)	0.4
Total other expenses (income)	2.1	2.2	(5.9)	4.9
Earnings before income taxes	22.2	28.0	43.4	38.0
Income tax expense	6.0	10.7	11.3	14.0
Net income	16.2	17.3	32.1	24.0
Less: Net income attributable to noncontrolling interest	0.9	1.1	1.5	1.8
Net income attributable to SP Plus Corporation	$ 15.3	$ 16.2	$ 30.6	$ 22.2
Net income per common share
Basic (in dollars per share)	$ 0.68	$ 0.73	$ 1.37	$ 1.00
Diluted (in dollars per share)	$ 0.68	$ 0.72	$ 1.36	$ 0.98
Weighted average shares outstanding
Basic (in shares)	22,370,923	22,190,421	22,335,835	22,178,143
Diluted (in shares)	22,644,884	22,515,234	22,597,131	22,490,369
Lease type contracts
Parking services revenue	$ 107.4	$ 150.9	$ 206.9	$ 281.7
Cost of parking services	94.5	130.2	189.0	256.0
Gross profit	12.9	20.7	17.9	25.7
Management type contracts
Parking services revenue	87.7	84.0	182.2	176.1
Cost of parking services	49.5	47.2	109.5	103.8
Gross profit	38.2	36.8	72.7	72.3
Cost of parking services
Parking services revenue	195.1	234.9	389.1	457.8
Cost of parking services	144.0	177.4	298.5	359.8
Reimbursed management type contract
Parking services revenue	167.1	168.6	339.9	347.6
Cost of parking services	$ 167.1	$ 168.6	$ 339.9	$ 347.6