Segment Information - Summarized Financial Information (Details) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2020 USD ($)	Jun. 30, 2019 USD ($)	Jun. 30, 2020 USD ($) segment	Jun. 30, 2019 USD ($)
Segment Reporting Information [Line Items]
Number of reporting segments | segment			2
Revenues	$ 293.1	$ 294.9	$ 583.8	$ 578.0
Expenses:
Operating expenses	155.5	159.4	317.9	319.4
Transition and integration costs	2.5	1.0	4.9	1.9
EBITDA	135.1	134.5	261.0	256.7
Depreciation and amortization	58.6	57.5	116.3	114.4
Operating income (loss)	76.5	77.0	144.7	142.3
Interest expense	(13.0)	(16.7)	(27.7)	(31.7)
Other income (expense), net	18.8	(0.5)	18.0	(0.8)
Earnings before income taxes and equity in losses of unconsolidated affiliates	82.3	59.8	135.0	109.8
Income tax expense	17.2	14.5	25.4	25.2
Earnings before equity in losses of unconsolidated affiliates	65.1	45.3	109.6	84.6
Equity in losses of unconsolidated affiliates, net of tax	(26.0)	(12.7)	(20.4)	(26.0)
Net earnings	39.1	32.6	89.2	58.6
Share-based compensation expense	9.5	12.1	20.2	25.4
Operating Segments | Software Solutions
Segment Reporting Information [Line Items]
Revenues	245.1	255.4	489.8	498.9
Expenses:
Operating expenses	98.9	101.5	204.2	204.3
Transition and integration costs		0.0	0.0	0.0
EBITDA	146.2	153.9	285.6	294.6
Depreciation and amortization	30.2	30.1	60.5	60.0
Operating income (loss)	116.0	123.8	225.1	234.6
Operating Segments | Data and Analytics
Segment Reporting Information [Line Items]
Revenues	48.2	39.7	94.3	79.4
Expenses:
Operating expenses	32.1	30.3	63.6	60.1
Transition and integration costs		0.0	0.0	0.0
EBITDA	16.1	9.4	30.7	19.3
Depreciation and amortization	3.8	3.9	7.8	7.7
Operating income (loss)	12.3	5.5	22.9	11.6
Corporate and Other
Segment Reporting Information [Line Items]
Revenues	(0.2)	(0.2)	(0.3)	(0.3)
Expenses:
Operating expenses	24.5	27.6	50.1	55.0
Transition and integration costs	2.5	1.0	4.9	1.9
EBITDA	(27.2)	(28.8)	(55.3)	(57.2)
Depreciation and amortization	24.6	23.5	48.0	46.7
Operating income (loss)	(51.8)	(52.3)	(103.3)	(103.9)
Share-based compensation expense	$ 9.5	$ 12.2	$ 21.2	$ 26.1