Consolidated Statements of Income - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Revenues:
Net premiums earned		$ 5,498.3	$ 5,253.4	$ 5,080.2
Title, escrow, and other fees		495.9	450.5	459.5
Total premiums and fees		5,994.2	5,703.9	5,539.7
Net investment income		450.7	431.8	409.4
Other income		132.6	121.6	102.2
Total operating revenues		6,577.6	6,257.4	6,051.5
Investment gains (losses):
Realized from actual transactions and impairments		36.6	58.2	211.6
Unrealized from changes in fair value of equity securities		599.5	(293.8)	0.0
Total realized and unrealized investment gains (losses)		636.1	(235.6)	211.6
Total revenues		7,213.7	6,021.8	6,263.1
Benefits, Claims and Expenses:
Benefits, claims and settlement expenses		2,545.3	2,440.9	2,459.2
Dividends to policyholders		27.3	19.8	19.5
Underwriting, acquisition, and other expenses		3,278.5	3,080.6	2,995.7
Interest and other charges		40.0	42.2	63.0
Total expenses		5,891.3	5,583.7	5,537.7
Income (loss) before income taxes (credits)		1,322.4	438.1	725.4
Income Taxes (Credits):
Current		238.4	114.1	132.6
Deferred		27.4	(46.5)	32.2
Total		265.9	67.5	164.8
Net Income (Loss)		$ 1,056.4	$ 370.5	$ 560.5
Net Income (Loss) Per Share:
Net income (loss) per share: basic (in dollars per share)		$ 3.52	$ 1.26	$ 2.14
Net income (loss) per share: diluted (in dollars per share)		$ 3.51	$ 1.24	$ 1.92
weighted average number of shares outstanding, basic		299,885,468	294,248,871	262,114,533
Weighted Average Number of Shares Outstanding, Diluted	[1]	301,227,715	301,016,076	299,387,373
Dividends Per Common Share:
Common Stock, Dividends, Per Share, Cash Paid		$ 1.80	$ 0.78	$ 1.76

[1] In calculating earnings per share, accounting standards require that common shares owned by the Company's Employee Savings and Stock Ownership Plan that are as yet unallocated to participants in the plan be excluded from the calculation. Such shares are issued and outstanding, and have the same voting and other rights applicable to all other common shares.