Condensed Consolidated Statements of Income - USD ($) shares in Millions, $ in Millions	3 Months Ended
	Mar. 31, 2025	Mar. 31, 2024
Income Statement [Abstract]
Revenue	$ 581.9	$ 542.8
Operating expense:
Cost of revenue	231.4	218.1
Sales and marketing	112.6	104.6
General and administrative	76.5	80.3
Depreciation and amortization	47.3	47.2
Total operating expense	467.8	450.2
Operating income	114.1	92.6
Non-operating expense, net:
Interest expense, net	(5.4)	(11.5)
Net realized gains on sale of investments, reclassified from other comprehensive income	0.3	2.6
Other income (expense), net	(0.5)	3.3
Non-operating expense, net	(5.6)	(5.6)
Income before income taxes and equity in investments of unconsolidated entities	108.5	87.0
Equity in investments of unconsolidated entities	(2.6)	(1.5)
Income tax expense	27.4	21.3
Consolidated net income	$ 78.5	$ 64.2
Net income per share:
Basic (in dollars per share)	$ 1.83	$ 1.50
Diluted (in dollars per share)	1.82	1.49
Dividends declared (in dollars per share)	0.46	0.41
Dividends paid per common share (in dollars per share)	$ 0.46	$ 0.41
Weighted average shares outstanding:
Basic (in shares)	42.8	42.7
Diluted (in shares)	43.1	43.0