Fair Values of Financial Instruments - Summary of Carrying or Reported Values and Corresponding Fair Values for Financial Instruments (Detail) - USD ($) $ in Thousands	Dec. 31, 2025	Dec. 31, 2024
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fixed maturity securities, fair value	$ 344,576	$ 399,721
Fixed maturity securities-available-for-sale	313,038	307,750
Equity securities	57,493	58,629
Short-term investments	14,237	9,338
Carrying Amount [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fixed maturity securities, fair value	350,087	413,061
Fixed maturity securities-available-for-sale	313,038	307,750
Equity securities	57,493	58,629
Short-term investments	14,237	9,338
Cash and cash equivalents	61,926	44,045
Fair Value [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fixed maturity securities, fair value	344,576	399,721
Fixed maturity securities-available-for-sale	313,038	307,750
Equity securities	57,493	58,629
Short-term investments	14,237	9,338
Cash and cash equivalents	$ 61,926	$ 44,045