Consolidated Statements of Income - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Revenues:
Net premiums earned	$ 6,445.9	$ 7,342.1	$ 7,559.8
Title, escrow, and other fees	261.8	333.2	443.8
Total premiums and fees	6,707.7	7,675.3	8,003.6
Net investment income	578.3	459.5	434.3
Other income	163.1	149.9	145.6
Total operating revenues	7,449.3	8,284.9	8,583.5
Net investment gains (losses):
Consolidated net realized investment gains (losses)	(67.0)	62.2	6.9
Unrealized from changes in fair value of equity securities	(123.9)	(263.4)	751.1
Total net investment gains (losses)	(190.9)	(201.1)	758.0
Total revenues	7,258.3	8,083.7	9,341.6
Expenses:
Loss and loss adjustment expenses	2,580.0	2,427.7	2,398.2
Dividends to policyholders	16.5	12.5	22.7
Underwriting, acquisition, and other expenses	3,843.6	4,719.2	4,942.3
Interest and other charges	70.5	66.7	56.2
Total expenses	6,510.8	7,226.3	7,419.5
Income before income taxes	747.4	857.4	1,922.1
Income Taxes (Credits):
Current	186.2	226.0	221.7
Deferred	(37.4)	(55.1)	165.9
Total	148.7	170.9	387.7
Net Income	$ 598.6	$ 686.4	$ 1,534.3
Net Income Per Share:
Net income per share: basic (in dollars per share)	$ 2.12	$ 2.28	$ 5.08
Net income per share: diluted (in dollars per share)	$ 2.10	$ 2.26	$ 5.05
Weighted average number of shares outstanding, basic	282,732,526	301,676,941	301,945,319
Weighted Average Number of Shares Outstanding, Diluted	285,471,064	303,296,612	303,667,669