Schedule I - Parent Company Financial Information - Balance Sheets (Parenthetical) (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Condensed Balance Sheet Statements, Captions [Line Items]
Trade and other	$ 49,453,000	$ 60,654,000
Accounts payable and accrued liabilities	$ 118,082,000	$ 111,965,000
Treasury stock, common shares	352,161	352,161
Common Stock
Condensed Balance Sheet Statements, Captions [Line Items]
Common stock, par value (usd per share)	$ 1	$ 1
Common stock, shares authorized	50,000,000	50,000,000
Common stock, shares issued	22,643,255	23,307,909
Common stock, shares outstanding	22,291,094	22,955,748
Class B Common Stock
Condensed Balance Sheet Statements, Captions [Line Items]
Common stock, par value (usd per share)	$ 1	$ 1
Common stock, shares authorized	1,500,000	1,500,000
Common stock, shares issued	1,050,012	1,050,012
Common stock, shares outstanding	1,050,012	1,050,012
Affiliates
Condensed Balance Sheet Statements, Captions [Line Items]
Trade and other	$ 120,000	$ 4,000
Accounts payable and accrued liabilities	4,000	0
Stewart Information Services Corporation - Parent Company
Condensed Balance Sheet Statements, Captions [Line Items]
Trade and other	1,093,000	497,000
Accounts payable and accrued liabilities	$ 22,781,000	$ 23,702,000
Treasury stock, common shares	352,161	352,161
Stewart Information Services Corporation - Parent Company | Common Stock
Condensed Balance Sheet Statements, Captions [Line Items]
Common stock, par value (usd per share)	$ 1	$ 1
Common stock, shares authorized	50,000,000	50,000,000
Common stock, shares issued	22,643,255	23,307,909
Common stock, shares outstanding	22,291,094	22,955,748
Stewart Information Services Corporation - Parent Company | Class B Common Stock
Condensed Balance Sheet Statements, Captions [Line Items]
Common stock, par value (usd per share)	$ 1	$ 1
Common stock, shares authorized	1,500,000	1,500,000
Common stock, shares issued	1,050,012	1,050,012
Common stock, shares outstanding	1,050,012	1,050,012
Subsidiaries
Condensed Balance Sheet Statements, Captions [Line Items]
Undistributed earnings	$ 514,522	$ 544,997