Fair Value Measurements - Financial Instruments (Details) - USD ($) $ in Thousands	Jun. 30, 2023	Dec. 31, 2022
Assets:
Total debt securities	$ 105,996	$ 110,201
Equity Securities	879	917
Short-term investments	39,564	25,929
Total marketable investments measured at fair value	146,439	137,047
Total assets measured at fair value	147,886	137,397
Liabilities:
Total Liabilities (non-recurring fair value measure)	35,123	33,730
U.S. Government
Assets:
Total debt securities	5,950	7,498
State and local government
Assets:
Total debt securities	21,698	20,816
Corporate debt
Assets:
Total debt securities	29,612	30,559
Asset-backed securities
Assets:
Total debt securities	19,523	20,496
Mortgage-backed securities
Assets:
Total debt securities	22,885	24,037
Commercial mortgage-backed securities
Assets:
Total debt securities	3,259	3,228
Collateralized mortgage obligations
Assets:
Total debt securities	3,069	3,567
Senior Unsecured Notes
Liabilities:
Debt	23,386	22,430
Subordinated notes
Liabilities:
Debt	11,737	11,300
Partnership interest
Assets:
Investments measured at NAV	1,447	350
Level 1
Assets:
Total debt securities	0	0
Equity Securities	122	160
Short-term investments	39,564	25,929
Total marketable investments measured at fair value	39,686	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 | Subordinated notes
Liabilities:
Debt	0	0
Level 2
Assets:
Total debt securities	105,996	110,201
Equity Securities	757	757
Short-term investments	0	0
Total marketable investments measured at fair value	106,753	110,958
Liabilities:
Total Liabilities (non-recurring fair value measure)	23,386	22,430
Level 2 | U.S. Government
Assets:
Total debt securities	5,950	7,498
Level 2 | State and local government
Assets:
Total debt securities	21,698	20,816
Level 2 | Corporate debt
Assets:
Total debt securities	29,612	30,559
Level 2 | Asset-backed securities
Assets:
Total debt securities	19,523	20,496
Level 2 | Mortgage-backed securities
Assets:
Total debt securities	22,885	24,037
Level 2 | Commercial mortgage-backed securities
Assets:
Total debt securities	3,259	3,228
Level 2 | Collateralized mortgage obligations
Assets:
Total debt securities	3,069	3,567
Level 2 | Senior Unsecured Notes
Liabilities:
Debt	23,386	22,430
Level 2 | Subordinated notes
Liabilities:
Debt	0	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)	11,737	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 | Subordinated notes
Liabilities:
Debt	$ 11,737	$ 11,300