Schedule I - Parent Company Financial Information - Statements of Operations and Retained Earnings (Detail) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Revenues
Investment income									$ 16,850	$ 16,806	$ 15,492
Other losses									(1,369)	6,744	(1,066)
Total revenues	$ 497,403	$ 555,704	$ 531,906	$ 448,872	$ 522,319	$ 508,097	$ 446,838	$ 393,576	2,033,885	1,870,830	1,927,980
Expenses
Employee costs									658,266	624,326	571,026
Other operating expenses, including $276 each year to affiliates									381,954	347,276	280,258
Depreciation and amortization									30,298	24,226	17,920
Interest									2,096	3,236	2,956
Total expenses									2,024,192	1,819,018	1,826,915
Income (loss) before taxes and (loss) income from subsidiaries									9,693	51,812	101,065
Income tax expense									5,650	13,503	28,481
Net (loss) income attributable to Stewart	2,605	$ (13,467)	$ 17,106	(12,448)	11,863	$ 23,717	$ 6,279	(12,106)	(6,204)	29,753	63,026
Retained earnings at beginning of year				479,733					479,733
Cash dividends on Common Stock									(18,010)	(2,334)	(2,159)
Retained earnings at end of year	455,519				479,733				455,519	479,733
Stewart Information Services Corporation - Parent Company
Revenues
Investment income									15,000	25,087	0
Other losses									0	(869)	(3,164)
Other income									922	90	263
Total revenues									15,922	24,308	(2,901)
Expenses
Employee costs									156	1,110	(91)
Other operating expenses, including $276 each year to affiliates									7,617	3,806	1,329
Depreciation and amortization									162	421	527
Interest									1,726	2,054	2,494
Total expenses									9,661	7,391	4,259
Income (loss) before taxes and (loss) income from subsidiaries									6,261	16,917	(7,160)
Income tax expense									0	1	24
(Loss) income from subsidiaries									(12,465)	12,837	70,210
Net (loss) income attributable to Stewart									(6,204)	29,753	63,026
Retained earnings at beginning of year				$ 479,733				$ 452,314	479,733	452,314	391,447
Cash dividends on Common Stock									(18,010)	(2,334)	(2,159)
Retained earnings at end of year	$ 455,519				$ 479,733				$ 455,519	$ 479,733	$ 452,314