Statutory surplus and dividend restrictions (Details) - Guaranty - Stewart Title Guaranty Company - USD ($)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Dividends Payable [Line Items]
Dividends paid by guaranty	$ 0	$ 150,000,000	$ 293,900,000
Maximum amount of dividend to be paid	168,700,000
Surplus for guaranty	843,300,000	790,400,000
Statutory net income	76,100,000	$ 144,900,000	$ 188,800,000
Statutory capital and surplus necessary to satisfy regulatory requirements for guaranty	2,000,000
Underwriter entities
Dividends Payable [Line Items]
Statutory capital and surplus necessary to satisfy regulatory requirements for guaranty	$ 2,000,000