Segment Information (Schedule of Selected Financial Information) (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Segment Reporting Information [Line Items]
Revenues	$ 1,508,344	$ 1,383,915	$ 4,071,589	$ 3,818,788
Income (loss) before income taxes	166,931	115,396	396,130	315,966
Depreciation and amortization	24,491	21,072	70,905	63,389
Capital expenditures	42,792	32,238	103,815	94,274
Operating Segments | Title Insurance and Services
Segment Reporting Information [Line Items]
Revenues	1,395,727	1,288,156	3,750,118	3,534,987
Income (loss) before income taxes	188,706	136,984	448,815	361,223
Depreciation and amortization	22,994	19,753	66,510	59,443
Capital expenditures	41,948	31,309	99,887	91,468
Operating Segments | Specialty Insurance
Segment Reporting Information [Line Items]
Revenues	109,782	101,210	317,246	293,398
Income (loss) before income taxes	1,781	1,684	18,744	29,446
Depreciation and amortization	1,401	1,197	4,107	3,579
Capital expenditures	844	927	3,928	2,804
Corporate
Segment Reporting Information [Line Items]
Revenues	2,855	(5,428)	4,265	(9,148)
Income (loss) before income taxes	(23,556)	(23,272)	(71,429)	(74,703)
Depreciation and amortization	96	122	288	367
Capital expenditures		2		2
Eliminations
Segment Reporting Information [Line Items]
Revenues	$ (20)	$ (23)	$ (40)	$ (449)