Fair Value Measurements - Financial Instruments (Details) - USD ($) $ in Thousands	Jun. 30, 2024	Dec. 31, 2023
Assets:
Total debt securities	$ 119,371	$ 122,113
Equity Securities	357	896
Short-term investments	23,339	20,838
Total marketable investments measured at fair value	143,067	143,847
Total assets measured at fair value	144,370	145,305
Liabilities:
Total Liabilities (non-recurring fair value measure)	27,197	21,756
U.S. Government
Assets:
Total debt securities	5,693	5,247
State and local government
Assets:
Total debt securities	20,126	20,464
Corporate debt
Assets:
Total debt securities	30,106	30,495
Asset-backed securities
Assets:
Total debt securities	37,002	37,752
Mortgage-backed securities
Assets:
Total debt securities	20,628	22,127
Commercial mortgage-backed securities
Assets:
Total debt securities	3,196	3,244
Collateralized mortgage obligations
Assets:
Total debt securities	2,620	2,784
Senior Unsecured Notes
Liabilities:
Debt	17,887	11,791
Senior Secured Notes
Liabilities:
Debt	9,310
Subordinated notes
Liabilities:
Debt		9,965
Partnership interest
Assets:
Investments measured at NAV	1,303	1,458
Level 1
Assets:
Total debt securities	0	0
Equity Securities	137	139
Short-term investments	23,339	20,838
Total marketable investments measured at fair value	23,476	20,977
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	119,371	122,113
Equity Securities	220	757
Short-term investments	0	0
Total marketable investments measured at fair value	119,591	122,870
Liabilities:
Total Liabilities (non-recurring fair value measure)	17,887	11,791
Level 2 | U.S. Government
Assets:
Total debt securities	5,693	5,247
Level 2 | State and local government
Assets:
Total debt securities	20,126	20,464
Level 2 | Corporate debt
Assets:
Total debt securities	30,106	30,495
Level 2 | Asset-backed securities
Assets:
Total debt securities	37,002	37,752
Level 2 | Mortgage-backed securities
Assets:
Total debt securities	20,628	22,127
Level 2 | Commercial mortgage-backed securities
Assets:
Total debt securities	3,196	3,244
Level 2 | Collateralized mortgage obligations
Assets:
Total debt securities	2,620	2,784
Level 2 | Senior Unsecured Notes
Liabilities:
Debt	17,887	11,791
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)	9,310	9,965
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	$ 9,310
Level 3 | Subordinated notes
Liabilities:
Debt		$ 9,965