Segment Information - Summary of Segment Information Reconciled to Consolidated Statements of Income (Parenthetical) (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024		Mar. 31, 2023
Segment Reporting Information [Line Items]
Gross premiums earned	$ 256,644	[1]	$ 180,068	[2]
Reinsurance [Member]
Segment Reporting Information [Line Items]
Gross premiums earned	6,111		4,535
HCPCI [Member]
Segment Reporting Information [Line Items]
Gross premiums earned	$ 149,271		$ 92,456

[1] Gross premiums earned under HCPCI Insurance Operations consist of $149,271 from HCPCI and $6,111 from a reinsurance company.

[2] Gross premiums earned under HCPCI Insurance Operations consist of $92,456 from HCPCI and $4,535 from a reinsurance company.