Significant Accounting Policies - Summary of Concentration of Credit Risk (Details) - Sales Revenue - Customer Concentration Risk	3 Months Ended
Mar. 31, 2022	Mar. 31, 2021
Government Solutions \| City of New York Department of Transportation
Concentration Risk [Line Items]
Concentration risk percentage	19.30%	24.40%
Commercial Services \| Hertz Corporation
Concentration Risk [Line Items]
Concentration risk percentage	11.10%	13.80%
Commercial Services \| Avis Budget Group, Inc.
Concentration Risk [Line Items]
Concentration risk percentage	11.40%	11.20%
Commercial Services \| Enterprise Holdings, Inc.
Concentration Risk [Line Items]
Concentration risk percentage	9.00%	14.50%

For an entity that discloses a concentration risk in relation to quantitative amount, which serves as the "benchmark" (or denominator) in the equation, this concept represents the concentration percentage derived from the division.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
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Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
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Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
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Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
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Reference 5: http://fasb.org/us-gaap/role/ref/legacyRef
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