Document and Entity Information - shares	6 Months Ended
	Jun. 30, 2018	Jul. 31, 2018
Document and Entity Information
Entity Registrant Name	SP Plus Corp
Entity Central Index Key	0001059262
Document Type	10-Q
Document Period End Date	Jun. 30, 2018
Amendment Flag	false
Current Fiscal Year End Date	--12-31
Entity Current Reporting Status	Yes
Entity Filer Category	Accelerated Filer
Entity Common Stock, Shares Outstanding (in shares)		22,729,564
Document Fiscal Year Focus	2018
Document Fiscal Period Focus	Q2