Segment Information (Schedule of Reportable Segment Performance Significant Expenses and Assets) (Detail) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2025		Mar. 31, 2024		Dec. 31, 2024
Segment Reporting Information [Line Items]
Total consolidated revenue	$ 1,582.3		$ 1,424.6
Less:
Personnel costs	506.7		484.9
Premiums retained by agents	525.5		447.8
Other operating expenses	278.3		265.8
Provision for policy losses	70.1		69.5
Depreciation and amortization	52.5		50.1
Premium taxes	17.4		13.9
Interest	35.2		34.3
Income before income taxes	96.6		58.3
Total assets	15,497.4		14,697.8		$ 14,908.6
Operating Segments
Segment Reporting Information [Line Items]
Total consolidated revenue	1,582.3	[1]	1,425.1	[2]
Less:
Personnel costs	506.8	[3]	484.8	[4]
Premiums retained by agents	525.5	[3]	447.8	[4]
Other operating expenses	278.3	[3],[5]	265.8	[4],[6]
Provision for policy losses	70.0	[3]	69.5	[4]
Depreciation and amortization	52.5	[3]	50.1	[4]
Premium taxes	17.4	[3]	13.9	[4]
Interest	35.2	[3]	34.9	[4]
Income before income taxes	96.6	[3]	57.8	[4]
Total assets	15,628.4		14,886.3
Segment capital expenditures	45.6		61.5
Operating Segments | Title Insurance and Services
Segment Reporting Information [Line Items]
Total consolidated revenue	1,484.4	[1]	1,319.8	[2]
Less:
Personnel costs	484.8	[3]	452.5	[4]
Premiums retained by agents	525.5	[3]	447.8	[4]
Other operating expenses	246.4	[3],[5]	233.7	[4],[6]
Provision for policy losses	33.4	[3]	29.0	[4]
Depreciation and amortization	51.2	[3]	48.8	[4]
Premium taxes	16.3	[3]	12.9	[4]
Interest	20.0	[3]	22.4	[4]
Income before income taxes	$ 106.8	[3]	$ 72.7	[4]
Pretax margin	7.20%		5.50%
Total assets	$ 14,616.5		$ 13,734.9
Segment capital expenditures	44.4		59.6
Operating Segments | Home Warranty
Segment Reporting Information [Line Items]
Total consolidated revenue	107.8	[1]	105.2	[2]
Less:
Personnel costs	20.5	[3]	19.8	[4]
Premiums retained by agents	0.0	[3]	0.0	[4]
Other operating expenses	22.5	[3],[5]	22.1	[4],[6]
Provision for policy losses	37.7	[3]	40.7	[4]
Depreciation and amortization	1.3	[3]	1.3	[4]
Premium taxes	1.1	[3]	1.0	[4]
Interest	0.0	[3]	0.0	[4]
Income before income taxes	$ 24.7	[3]	$ 20.3	[4]
Pretax margin	22.90%		19.30%
Total assets	$ 377.1		$ 353.9
Segment capital expenditures	1.2		1.9
Operating Segments | Corporate and Eliminations
Segment Reporting Information [Line Items]
Total consolidated revenue	(9.9)		(0.4)
Operating Segments | Corporate
Segment Reporting Information [Line Items]
Total consolidated revenue	(9.9)	[1]	0.1	[2]
Less:
Personnel costs	1.5	[3]	12.5	[4]
Premiums retained by agents	0.0	[3]	0.0	[4]
Other operating expenses	9.4	[3],[5]	10.0	[4],[6]
Provision for policy losses	(1.1)	[3]	(0.2)	[4]
Depreciation and amortization	0.0	[3]	0.0	[4]
Premium taxes	0.0	[3]	0.0	[4]
Interest	15.2	[3]	12.5	[4]
Income before income taxes	(34.9)	[3]	(34.7)	[4]
Total assets	634.8		797.5
Eliminations
Segment Reporting Information [Line Items]
Total consolidated revenue	0.0		(0.5)
Less:
Income before income taxes	0.0		0.5
Total assets	$ (131.0)	[7]	$ (188.5)	[8]

[1] Intersegment revenue is included within amounts shown.

[2] Intersegment revenue is included within amounts shown.

[3] The significant expense categories and amounts align with segment level information that is regularly provided to the chief operating decision maker. Intersegment expenses are included within amounts shown.

[4] The significant expense categories and amounts align with segment level information that is regularly provided to the chief operating decision maker. Intersegment expenses are included within amounts shown.

[5] Other operating expenses for each segment primarily include the following: Title insurance and services - title and data search expenses, office and occupancy expenses and software expense. Home warranty - advertising expense, office and occupancy expenses, software expense, delivery and storage expenses. Corporate - employee benefit expense and certain overhead expenses.

[6] Other operating expenses for each segment primarily include the following: Title insurance and services - title and data search expenses, office and occupancy expenses and software expense. Home warranty - advertising expense, office and occupancy expenses, software expense, delivery and storage expenses. Corporate - employee benefit expense and certain overhead expenses.

[7] Elimination of intercompany asset balances: Holding company cash balances also included in the title insurance and services segment   $ (131.0 )   For the three months ended March 31, 2024:

[8] Elimination of intercompany asset balances: Holding company cash balances also included in the title insurance segment and services segment   $ (112.3 ) Holding company receivable from a subsidiary within the title insurance and services segment     (76.2 )     $ (188.5 ) (5)