Fair Value of Financial Instruments - Financial Instruments Measured at Fair Value (Details) - USD ($)	Mar. 31, 2025	Dec. 31, 2024
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Fixed Maturity, Available-for-Sale	$ 1,931,091,000	$ 1,868,331,000
US Treasury and government agencies
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Fixed Maturity, Available-for-Sale	118,394,000	117,301,000
States, municipalities and political subdivisions
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Fixed Maturity, Available-for-Sale	263,431,000	247,904,000
Corporate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Fixed Maturity, Available-for-Sale	676,193,000	689,382,000
Residential mortgage-backed
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Fixed Maturity, Available-for-Sale	605,750,000	583,411,000
Commercial mortgage-backed
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Fixed Maturity, Available-for-Sale	130,549,000	103,554,000
Other asset-backed
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Fixed Maturity, Available-for-Sale	136,774,000	126,779,000
Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Fixed Maturity, Available-for-Sale	1,931,091,000	1,868,331,000
Short-Term Investments	590,000	100,000
Cash and cash equivalents	35,968,000	23,098,000
Corporate-Owned Life Insurance	12,838,000	13,003,000
Total Assets Measured at Fair Value	1,980,487,000	1,904,532,000
Recurring | US Treasury and government agencies
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Fixed Maturity, Available-for-Sale	118,394,000	117,301,000
Recurring | States, municipalities and political subdivisions
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Fixed Maturity, Available-for-Sale	263,431,000	247,904,000
Recurring | Corporate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Fixed Maturity, Available-for-Sale	676,193,000	689,382,000
Recurring | Residential mortgage-backed
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Fixed Maturity, Available-for-Sale	605,750,000	583,411,000
Recurring | Commercial mortgage-backed
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Fixed Maturity, Available-for-Sale	130,549,000	103,554,000
Recurring | Other asset-backed
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Fixed Maturity, Available-for-Sale	136,774,000	126,779,000
Recurring | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Fixed Maturity, Available-for-Sale	33,071,000	30,914,000
Short-Term Investments	100,000	100,000
Cash and cash equivalents	35,968,000	23,098,000
Corporate-Owned Life Insurance	0	0
Total Assets Measured at Fair Value	69,139,000	54,112,000
Recurring | Level 1 | US Treasury and government agencies
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Fixed Maturity, Available-for-Sale	33,071,000	30,914,000
Recurring | Level 1 | States, municipalities and political subdivisions
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Fixed Maturity, Available-for-Sale	0	0
Recurring | Level 1 | Corporate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Fixed Maturity, Available-for-Sale	0
Recurring | Level 1 | Residential mortgage-backed
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Fixed Maturity, Available-for-Sale	0	0
Recurring | Level 1 | Commercial mortgage-backed
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Fixed Maturity, Available-for-Sale	0	0
Recurring | Level 1 | Other asset-backed
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Fixed Maturity, Available-for-Sale	0
Recurring | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Fixed Maturity, Available-for-Sale	1,898,020,000	1,837,417,000
Short-Term Investments	490,000	0
Cash and cash equivalents	0	0
Corporate-Owned Life Insurance	12,838,000	13,003,000
Total Assets Measured at Fair Value	1,911,348,000	1,850,420,000
Recurring | Level 2 | US Treasury and government agencies
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Fixed Maturity, Available-for-Sale	85,323,000	86,387,000
Recurring | Level 2 | States, municipalities and political subdivisions
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Fixed Maturity, Available-for-Sale	263,431,000	247,904,000
Recurring | Level 2 | Corporate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Fixed Maturity, Available-for-Sale	676,193,000	689,382,000
Recurring | Level 2 | Residential mortgage-backed
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Fixed Maturity, Available-for-Sale	605,750,000	583,411,000
Recurring | Level 2 | Commercial mortgage-backed
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Fixed Maturity, Available-for-Sale	130,549,000	103,554,000
Recurring | Level 2 | Other asset-backed
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Fixed Maturity, Available-for-Sale	136,774,000	126,779,000
Recurring | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Fixed Maturity, Available-for-Sale	0	0
Short-Term Investments	0	0
Cash and cash equivalents	0	0
Corporate-Owned Life Insurance	0	0
Total Assets Measured at Fair Value	0	0
Recurring | Level 3 | US Treasury and government agencies
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Fixed Maturity, Available-for-Sale	0	0
Recurring | Level 3 | States, municipalities and political subdivisions
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Fixed Maturity, Available-for-Sale	0	0
Recurring | Level 3 | Corporate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Fixed Maturity, Available-for-Sale	0	0
Recurring | Level 3 | Residential mortgage-backed
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Fixed Maturity, Available-for-Sale	0	0
Recurring | Level 3 | Commercial mortgage-backed
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Fixed Maturity, Available-for-Sale	0	0
Recurring | Level 3 | Other asset-backed
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Fixed Maturity, Available-for-Sale	$ 0	$ 0