Schedule I - Financial Information of the Registrant (Parent Company) - Statements of Cash Flows (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Reconciliation of net income to cash provided (used) by operating activities:
Net income attributable to Stewart	$ (31)	$ 66,108	$ 19,306	$ (6,768)	$ 11,373	$ 17,554	$ 22,377	$ (3,781)	$ 78,615	$ 47,523	$ 48,659
Add (deduct):
Depreciation									22,526	24,932	25,878
(Increase) decrease in receivables – net									(2,917)	5,280	(7,667)
Decrease (increase) in other assets – net									6,865	4,469	(4,512)
Increase (decrease) in payables and accrued liabilities – net									31,471	(12,002)	1,933
Income from subsidiaries									(3,044)	(1,940)	(2,163)
Other – net									252	404	483
Cash provided (used) by operating activities									166,359	84,177	108,068
Investing activities:
Cash provided (used) by investing activities									7,040	9,379	(103,035)
Financing activities:
Proceeds from notes payable									30,464	14,530	56,493
Payments on notes payable									(27,868)	(20,118)	(56,467)
Dividends paid									(28,345)	(28,263)	(28,135)
Repurchases of Common Stock									(532)	(1,175)	(727)
Purchase of remaining interest of consolidated subsidiary									0	(1,101)	(1,810)
Other – net									25	0	(1,298)
Cash used by financing activities									(37,762)	(47,758)	(43,595)
Increase (decrease) in cash and cash equivalents									138,542	41,988	(35,693)
Cash and cash equivalents at beginning of year				192,067				150,079	192,067	150,079	185,772
Cash and cash equivalents at end of year	330,609				192,067				330,609	192,067	150,079
Supplemental information:
Income taxes paid									11,992	12,854	(1,642)
Interest paid									4,241	4,214	3,466
Parent Company
Reconciliation of net income to cash provided (used) by operating activities:
Net income attributable to Stewart									78,615	47,523	48,659
Add (deduct):
Depreciation									8	4	5
(Increase) decrease in receivables – net									(253)	922	(81)
Decrease (increase) in other assets – net									1,659	853	(1,576)
Increase (decrease) in payables and accrued liabilities – net									2,698	(4,476)	563
Income from subsidiaries									(44,770)	(40,669)	(36,062)
Other – net									1,530	(5,124)	1,705
Cash provided (used) by operating activities									39,487	(967)	13,213
Investing activities:
Dividends from subsidiary									0	25,000	20,000
Collections on notes receivables									1,416	24,900	23,375
Increases in notes receivables									0	(5,193)	(16,000)
Contributions to a subsidiary									0	0	(7,184)
Cash provided (used) by investing activities									1,416	44,707	20,191
Financing activities:
Proceeds from notes payable									0	0	16,000
Payments on notes payable									0	0	(10,000)
Dividends paid									(28,345)	(28,263)	(28,135)
Repurchases of Common Stock									(532)	(1,175)	(727)
Purchase of remaining interest of consolidated subsidiary									0	(1,101)	(1,810)
Other – net									0	0	0
Cash used by financing activities									(28,877)	(30,539)	(24,672)
Increase (decrease) in cash and cash equivalents									12,026	13,201	8,732
Cash and cash equivalents at beginning of year				$ 24,823				$ 11,622	24,823	11,622	2,890
Cash and cash equivalents at end of year	$ 36,849				$ 24,823				36,849	24,823	11,622
Supplemental information:
Income taxes paid									0	0	0
Interest paid									$ 4,009	$ 3,849	$ 3,128