Segment Information - Supplemental Geographic and Customer Solution Set Information (Details) - USD ($) $ in Millions		1 Months Ended	3 Months Ended		9 Months Ended
		Feb. 07, 2019	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Segment Reporting Information [Line Items]
Revenue	[1]	$ 178.7	$ 442.1	$ 408.2	$ 1,258.0	$ 981.2
Finance & Risk
Segment Reporting Information [Line Items]
Revenue		104.6	272.5	243.4	762.3	585.3
Sales & Marketing
Segment Reporting Information [Line Items]
Revenue		74.1	169.6	164.8	495.7	395.9
Operating Segments | North America
Segment Reporting Information [Line Items]
Revenue		148.2	363.3	374.7	1,059.1	916.8
Operating Segments | North America | Finance & Risk
Segment Reporting Information [Line Items]
Revenue		80.4	206.6	208.4	593.2	511.1
Operating Segments | North America | Sales & Marketing
Segment Reporting Information [Line Items]
Revenue		67.8	156.7	166.3	465.9	405.7
Operating Segments | International
Segment Reporting Information [Line Items]
Revenue		56.4	79.8	72.7	219.4	163.7
Operating Segments | International | Finance & Risk
Segment Reporting Information [Line Items]
Revenue		43.4	66.3	58.1	179.7	133.8
Operating Segments | International | Sales & Marketing
Segment Reporting Information [Line Items]
Revenue		13.0	13.5	14.6	39.7	29.9
Corporate and other
Segment Reporting Information [Line Items]
Revenue		(25.9)	(1.0)	(39.2)	(20.5)	(99.3)
Corporate and other | Finance & Risk
Segment Reporting Information [Line Items]
Revenue		(19.2)	(0.4)	(23.1)	(10.6)	(59.6)
Corporate and other | Sales & Marketing
Segment Reporting Information [Line Items]
Revenue		$ (6.7)	$ (0.6)	$ (16.1)	$ (9.9)	$ (39.7)

[1] See Note 1 "Basis of Presentation" for further discussion.