Business Unit Segment Information (Details) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2015 USD ($)	Jun. 30, 2014 USD ($)	Jun. 30, 2015 USD ($) item	Jun. 30, 2014 USD ($)
Business Unit Segment Information
Number of operating segments \| item			6
Revenues
Lease contracts	$ 146,454	$ 124,958	$ 282,269	$ 241,593
Management contracts	88,305	84,931	182,363	174,886
Reimbursed management contract revenue	170,856	164,539	345,137	333,717
Total revenue	405,615	374,428	809,769	750,196
Gross profit
Lease contracts	11,980	12,979	19,102	17,530
Management contracts	34,455	34,915	68,523	65,656
Total gross profit	46,435	47,894	87,625	83,186
Gross Margin
General and administrative expenses	$ 24,739	$ 24,996	$ 50,412	$ 51,062
General and administrative expense percentage of gross profit	53.00%	52.00%	58.00%	61.00%
Depreciation and amortization	$ 8,165	$ 7,730	$ 16,099	$ 14,893
Operating income	13,531	15,168	21,114	17,231
Other expenses (income)
Interest expense	3,062	4,811	7,105	9,620
Interest income	(40)	(94)	(100)	(192)
Equity in losses from investment in unconsolidated entity	353		824
Total other expenses (income)	3,375	4,717	7,829	9,428
Income before income taxes	10,156	10,451	13,285	7,803
Income tax (benefit)	(385)	4,254	950	(3,184)
Net income	10,541	6,197	12,335	10,987
Less: Net income attributable to noncontrolling interest	784	890	1,236	1,377
Net income attributable to SP Plus Corporation	9,757	5,307	11,099	9,610
Other
Revenues
Reimbursed management contract revenue	170,856	164,539	345,137	333,717
Total revenue	405,615	374,428	809,769	750,196
Operating segment \| Region One
Revenues
Lease contracts	51,489	52,315	98,713	99,650
Management contracts	19,883	21,070	40,004	42,784
Total parking services revenue	71,372	73,385	138,717	142,434
Gross profit
Lease contracts	4,090	4,192	5,632	4,769
Management contracts	8,864	8,849	18,255	17,958
Total gross profit	$ 12,954	$ 13,041	$ 23,887	$ 22,727
Gross Margin
Lease contracts (as a percent)	8.00%	8.00%	6.00%	5.00%
Management contracts (as a percent)	45.00%	42.00%	46.00%	42.00%
Operating segment \| Region Two
Revenues
Lease contracts	$ 33,775	$ 30,499	$ 65,003	$ 59,259
Management contracts	21,078	22,300	41,526	41,245
Total parking services revenue	54,853	52,799	106,529	100,504
Gross profit
Lease contracts	6,842	5,941	11,367	9,661
Management contracts	8,808	9,959	16,810	17,683
Total gross profit	$ 15,650	$ 15,900	$ 28,177	$ 27,344
Gross Margin
Lease contracts (as a percent)	20.00%	19.00%	17.00%	16.00%
Management contracts (as a percent)	42.00%	45.00%	40.00%	43.00%
Operating segment \| Region Three
Revenues
Lease contracts	$ 27,652	$ 29,521	$ 54,057	$ 57,532
Management contracts	6,788	5,536	13,506	12,650
Total parking services revenue	34,440	35,057	67,563	70,182
Gross profit
Lease contracts	1,031	1,052	565	887
Management contracts	3,359	2,825	6,764	7,021
Total gross profit	$ 4,390	$ 3,877	$ 7,329	$ 7,908
Gross Margin
Lease contracts (as a percent)	4.00%	4.00%	1.00%	2.00%
Management contracts (as a percent)	49.00%	51.00%	50.00%	56.00%
Operating segment \| Region Four
Revenues
Lease contracts	$ 32,370	$ 11,233	$ 62,077	$ 22,583
Management contracts	26,114	25,859	51,585	52,573
Total parking services revenue	58,484	37,092	113,662	75,156
Gross profit
Lease contracts	1,691	962	2,554	1,561
Management contracts	7,187	7,229	12,700	13,623
Total gross profit	$ 8,878	$ 8,191	$ 15,254	$ 15,184
Gross Margin
Lease contracts (as a percent)	5.00%	9.00%	4.00%	7.00%
Management contracts (as a percent)	28.00%	28.00%	25.00%	26.00%
Operating segment \| Region Five
Revenues
Lease contracts	$ 1,159	$ 1,286	$ 2,400	$ 2,483
Management contracts	10,858	8,120	28,415	21,046
Total parking services revenue	12,017	9,406	30,815	23,529
Gross profit
Lease contracts	(22)	14	179	131
Management contracts	2,742	2,680	6,450	6,272
Total gross profit	$ 2,720	$ 2,694	$ 6,629	$ 6,403
Gross Margin
Lease contracts (as a percent)	(2.00%)	1.00%	7.00%	5.00%
Management contracts (as a percent)	25.00%	33.00%	23.00%	30.00%
Operating segment \| Other
Revenues
Lease contracts	$ 9	$ 104	$ 19	$ 86
Management contracts	3,584	2,046	7,327	4,588
Total parking services revenue	3,593	2,150	7,346	4,674
Gross profit
Lease contracts	(1,652)	818	(1,195)	521
Management contracts	3,495	3,373	7,544	3,099
Total gross profit	$ 1,843	$ 4,191	$ 6,349	$ 3,620
Gross Margin
Lease contracts (as a percent)	(18356.00%)	787.00%	(6289.00%)	606.00%
Management contracts (as a percent)	98.00%	165.00%	103.00%	68.00%

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