Net Income per Common Share (Tables)

6 Months Ended

Jun. 30, 2018

Earnings Per Share [Abstract]

Schedule of Reconciliation of Weighted Average Shares

A reconciliation of the weighted average basic common shares outstanding to the weighted average diluted common shares outstanding is as follows:

	Three Months Ended				Six Months Ended
(millions, except share and per share data) (unaudited)	June 30, 2018		June 30, 2017		June 30, 2018		June 30, 2017
Net income attributable to SP Plus Corporation	$	15.3	$	16.2	$	30.6	$	22.2
Basic weighted average common shares outstanding	22,370,923		22,190,421		22,335,835		22,178,143
Dilutive impact of share-based awards	273,961		324,813		261,296		312,226
Diluted weighted average common shares outstanding	22,644,884		22,515,234		22,597,131		22,490,369
Net income per common share
Basic	$	0.68	$	0.73	$	1.37	$	1.00
Diluted	$	0.68	$	0.72	$	1.36	$	0.98