Goodwill and Other Intangible Assets, net - Narrative (Details) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2021 USD ($) reporting_unit	Jun. 30, 2020 USD ($)	Jun. 30, 2021 USD ($)	Jun. 30, 2020 USD ($)
Schedule of Other Intangible Assets by Major Class [Line Items]
Gain (loss) on disposition of business	$ (6.8)	$ 0.0	$ (6.8)	$ 0.0
Amortization expense	19.9	$ 18.6	40.7	$ 37.7
Finite-Lived Intangible Assets, Net, Amortization Expense, Fiscal Year Maturity [Abstract]
Remainder of 2021	39.1		39.1
2022	73.1		73.1
2023	68.4		68.4
2024	63.5		63.5
2025	58.9		58.9
2026	$ 55.2		$ 55.2
Percentage of definite-lived intangible assets under accelerated amortization method (approximate)	76.00%		76.00%
Number of reporting units step zero test | reporting_unit	1
Number of reporting units with goodwill | reporting_unit	5
Number of reporting units excluded from step zero test | reporting_unit	4
Consumer Analytics Solutions Business | Disposal Group, Disposed of by Sale, Not Discontinued Operations
Schedule of Other Intangible Assets by Major Class [Line Items]
Discontinued operation consideration	$ 9.8		$ 9.8
Dispositions, assets	15.9		15.9
Dispositions, definite-lived intangibles	8.7		8.7
Dispositions, goodwill	1.9		1.9
Dispositions, liabilities	1.5		1.5
Gain (loss) on disposition of business	$ (6.8)		$ (6.8)