Fair Value Measurements - Financial Instruments (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Assets:
Total debt securities	$ 122,113	$ 110,201
Equity Securities	896	917
Short-term investments	20,838	25,929
Total marketable investments measured at fair value	143,847	137,047
Total assets measured at fair value	145,305	137,397
Liabilities:
Total Liabilities (non-recurring fair value measure)	21,756	33,730
U.S. Government
Assets:
Total debt securities	5,247	7,498
State and local government
Assets:
Total debt securities	20,464	20,816
Corporate debt
Assets:
Total debt securities	30,495	30,559
Asset-backed securities
Assets:
Total debt securities	37,752	20,496
Mortgage-backed securities
Assets:
Total debt securities	22,127	24,037
Commercial mortgage-backed securities
Assets:
Total debt securities	3,244	3,228
Collateralized mortgage obligations
Assets:
Total debt securities	2,784	3,567
Senior Unsecured Notes
Liabilities:
Debt	11,791	22,430
Senior Secured Notes
Liabilities:
Debt	9,965
Subordinated notes
Liabilities:
Debt		11,300
Partnership interest
Assets:
Investments measured at NAV	1,458	350
Level 1
Assets:
Total debt securities	0	0
Equity Securities	139	160
Short-term investments	20,838	25,929
Total marketable investments measured at fair value	20,977	26,089
Liabilities:
Total Liabilities (non-recurring fair value measure)	0	0
Level 1 | U.S. Government
Assets:
Total debt securities	0	0
Level 1 | State and local government
Assets:
Total debt securities	0	0
Level 1 | Corporate debt
Assets:
Total debt securities	0	0
Level 1 | Asset-backed securities
Assets:
Total debt securities	0	0
Level 1 | Mortgage-backed securities
Assets:
Total debt securities	0	0
Level 1 | Commercial mortgage-backed securities
Assets:
Total debt securities	0	0
Level 1 | Collateralized mortgage obligations
Assets:
Total debt securities	0	0
Level 1 | Senior Unsecured Notes
Liabilities:
Debt	0	0
Level 1 | Senior Secured Notes
Liabilities:
Debt	0
Level 1 | Subordinated notes
Liabilities:
Debt		0
Level 2
Assets:
Total debt securities	122,113	110,201
Equity Securities	757	757
Short-term investments	0	0
Total marketable investments measured at fair value	122,870	110,958
Liabilities:
Total Liabilities (non-recurring fair value measure)	11,791	22,430
Level 2 | U.S. Government
Assets:
Total debt securities	5,247	7,498
Level 2 | State and local government
Assets:
Total debt securities	20,464	20,816
Level 2 | Corporate debt
Assets:
Total debt securities	30,495	30,559
Level 2 | Asset-backed securities
Assets:
Total debt securities	37,752	20,496
Level 2 | Mortgage-backed securities
Assets:
Total debt securities	22,127	24,037
Level 2 | Commercial mortgage-backed securities
Assets:
Total debt securities	3,244	3,228
Level 2 | Collateralized mortgage obligations
Assets:
Total debt securities	2,784	3,567
Level 2 | Senior Unsecured Notes
Liabilities:
Debt	11,791	22,430
Level 2 | Senior Secured Notes
Liabilities:
Debt	0
Level 2 | Subordinated notes
Liabilities:
Debt		0
Level 3
Assets:
Total debt securities	0	0
Equity Securities	0	0
Short-term investments	0	0
Total marketable investments measured at fair value	0	0
Liabilities:
Total Liabilities (non-recurring fair value measure)	9,965	11,300
Level 3 | U.S. Government
Assets:
Total debt securities	0	0
Level 3 | State and local government
Assets:
Total debt securities	0	0
Level 3 | Corporate debt
Assets:
Total debt securities	0	0
Level 3 | Asset-backed securities
Assets:
Total debt securities	0	0
Level 3 | Mortgage-backed securities
Assets:
Total debt securities	0	0
Level 3 | Commercial mortgage-backed securities
Assets:
Total debt securities	0	0
Level 3 | Collateralized mortgage obligations
Assets:
Total debt securities	0	0
Level 3 | Senior Unsecured Notes
Liabilities:
Debt	0	0
Level 3 | Senior Secured Notes
Liabilities:
Debt	$ 9,965
Level 3 | Subordinated notes
Liabilities:
Debt		$ 11,300