Schedule I - Financial Information of the Registrant (Parent Company) - Statements of Income and Retained Earnings (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Expenses
Interest	$ 18,403	$ 5,031	$ 2,624
Other operating expenses	648,022	626,762	375,188
Total expenses	2,836,644	2,871,821	2,069,927
Income tax expense	(50,864)	(93,989)	(48,833)
Net income attributable to Stewart	162,305	323,216	154,905
Retained Earnings [Roll Forward]
Retained earnings at beginning of year	974,800
Retained earnings at end of year	1,091,816	974,800
Parent company
Revenues
Interest income and other net realized (losses) gains	(1,639)	(281)	1,182
Expenses
Interest	18,276	5,101	2,511
Other operating expenses	8,161	6,924	9,262
Total expenses	26,437	12,025	11,773
Loss before taxes and income from investments in subsidiaries	(28,076)	(12,306)	(10,591)
Income tax expense	(8)	0	(15)
Income from investments in subsidiaries	190,389	335,522	165,511
Net income attributable to Stewart	162,305	323,216	154,905
Retained Earnings [Roll Forward]
Retained earnings at beginning of year	974,800	688,819	564,392
Cash dividends on Common Stock	(45,289)	(37,235)	(30,478)
Retained earnings at end of year	$ 1,091,816	$ 974,800	$ 688,819