Segment Information (Schedule of Selected Financial Information) (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Segment Reporting Information [Line Items]
Revenues	$ 1,303,581	$ 1,297,388
Income (loss) before income taxes	141,670	93,065
Depreciation and amortization	32,934	29,747
Capital expenditures	27,976	23,601
Direct premiums and escrow fees	514,202	543,878
Agent premiums	501,537	527,714
Information and other	172,892	188,658
Net investment income	82,268	42,792
Net realized investment gains (losses)	32,682	(5,654)
Operating Segments
Segment Reporting Information [Line Items]
Revenues	1,294,362	1,298,851
Direct premiums and escrow fees	514,202	543,878
Agent premiums	501,537	527,714
Information and other	173,156	188,924
Net investment income	72,785	43,989
Net realized investment gains (losses)	32,682	(5,654)
Operating Segments | Title Insurance and Services
Segment Reporting Information [Line Items]
Revenues	1,172,180	1,185,467
Income (loss) before income taxes	142,007	102,384
Depreciation and amortization	31,162	28,117
Capital expenditures	25,479	21,070
Direct premiums and escrow fees	402,756	434,152
Agent premiums	501,537	527,714
Information and other	170,089	186,023
Net investment income	70,053	41,401
Net realized investment gains (losses)	27,745	(3,823)
Operating Segments | Specialty Insurance
Segment Reporting Information [Line Items]
Revenues	122,182	113,384
Income (loss) before income taxes	17,785	9,898
Depreciation and amortization	1,734	1,592
Capital expenditures	2,497	2,531
Direct premiums and escrow fees	111,446	109,726
Agent premiums	0	0
Information and other	3,067	2,901
Net investment income	2,732	2,588
Net realized investment gains (losses)	4,937	(1,831)
Corporate
Segment Reporting Information [Line Items]
Revenues	9,559	(1,182)
Income (loss) before income taxes	(18,122)	(19,217)
Depreciation and amortization	38	38
Capital expenditures	0	0
Eliminations
Segment Reporting Information [Line Items]
Revenues	(340)	(281)
Income (loss) before income taxes	0	0
Depreciation and amortization	0	0
Capital expenditures	$ 0	$ 0