Fair Value Measurements - Financial Instruments (Details) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Assets:
Total debt securities	$ 115,161	$ 122,113
Equity Securities	331	896
Short-term investments	21,255	20,838
Total marketable investments measured at fair value	136,747	143,847
Investments measured at NAV	$ 1,294	$ 1,458
Investment, Type [Extensible Enumeration]	Partnership Interest [Member]	Partnership Interest [Member]
Total investments measured at fair value	$ 138,041
Total assets measured at fair value	150,965	$ 145,305
Liabilities:
Total Liabilities (non-recurring fair value measure)	13,300	21,756
CIS
Assets:
Contingent considerations from CIS sale	12,924
U.S. Government
Assets:
Total debt securities	5,344	5,247
State and local government
Assets:
Total debt securities	19,924	20,464
Corporate debt
Assets:
Total debt securities	31,187	30,495
Asset-backed securities
Assets:
Total debt securities	32,678	37,752
Mortgage-backed securities
Assets:
Total debt securities	21,176	22,127
Commercial mortgage-backed securities
Assets:
Total debt securities	2,218	3,244
Collateralized mortgage obligations
Assets:
Total debt securities	2,634	2,784
Senior Unsecured Notes
Liabilities:
Debt	13,300	11,791
Subordinated notes
Liabilities:
Debt		9,965
Level 1
Assets:
Total debt securities	0	0
Equity Securities	111	139
Short-term investments	21,255	20,838
Total marketable investments measured at fair value	21,366	20,977
Liabilities:
Total Liabilities (non-recurring fair value measure)	0	0
Level 1 | CIS
Assets:
Contingent considerations from CIS sale	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 | Subordinated notes
Liabilities:
Debt		0
Level 2
Assets:
Total debt securities	115,161	122,113
Equity Securities	220	757
Short-term investments	0	0
Total marketable investments measured at fair value	115,381	122,870
Liabilities:
Total Liabilities (non-recurring fair value measure)	13,300	11,791
Level 2 | CIS
Assets:
Contingent considerations from CIS sale	0
Level 2 | U.S. Government
Assets:
Total debt securities	5,344	5,247
Level 2 | State and local government
Assets:
Total debt securities	19,924	20,464
Level 2 | Corporate debt
Assets:
Total debt securities	31,187	30,495
Level 2 | Asset-backed securities
Assets:
Total debt securities	32,678	37,752
Level 2 | Mortgage-backed securities
Assets:
Total debt securities	21,176	22,127
Level 2 | Commercial mortgage-backed securities
Assets:
Total debt securities	2,218	3,244
Level 2 | Collateralized mortgage obligations
Assets:
Total debt securities	2,634	2,784
Level 2 | Senior Unsecured Notes
Liabilities:
Debt	13,300	11,791
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)	0	9,965
Level 3 | CIS
Assets:
Contingent considerations from CIS sale	12,924
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 | Subordinated notes
Liabilities:
Debt		$ 9,965