Fair Value - Rollforward of Level 3 assets and liabilities (Details) - Recurring - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
		Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Other liabilities
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance at beginning of period		$ (17,591)	$ (465)	$ (16,960)	$ (461)
Total gains or (losses) (realized/unrealized) - included in earnings	[1]	(97)	(1)	(195)	(5)
Total gains or (losses) (realized/unrealized) - included in other comprehensive income		1,483	0	950	0
Purchases, issuances, sales and settlements
Purchases		0	0	0	0
Issuances		0	0	0	0
Sales		0	0	0	0
Settlements		0	0	0	0
Transfers in and/or out of Level 3		0	0	0	0
Balance at end of period		(16,205)	(466)	(16,205)	(466)
Available for sale | Structured securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance at beginning of period	[2]	3,152	3,472	3,347	3,426
Total gains or (losses) (realized/unrealized) - included in earnings	[1],[2]	(1)	12	9	(56)
Total gains or (losses) (realized/unrealized) - included in other comprehensive income	[2]	(85)	(57)	(145)	57
Purchases, issuances, sales and settlements
Purchases	[2]	0	0	0	0
Issuances	[2]	0	0	0	0
Sales	[2]	0	0	0	0
Settlements	[2]	(199)	(3)	(344)	(3)
Transfers in and/or out of Level 3	[2]	0	0	0	0
Balance at end of period	[2]	2,867	3,424	2,867	3,424
Available for sale | Corporate bonds
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance at beginning of period		3,570	13	13	13
Total gains or (losses) (realized/unrealized) - included in earnings	[1]	0	0	0	0
Total gains or (losses) (realized/unrealized) - included in other comprehensive income		0	0	0	0
Purchases, issuances, sales and settlements
Purchases		0	0	0	0
Issuances		0	0	0	0
Sales		0	0	0	0
Settlements		0	0	0	0
Transfers in and/or out of Level 3		0	0	3,557	0
Balance at end of period		3,570	13	3,570	13
Fair value option | Corporate bonds
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance at beginning of period		0	989	0	985
Total gains or (losses) (realized/unrealized) - included in earnings	[1]	0	9	0	13
Total gains or (losses) (realized/unrealized) - included in other comprehensive income		0	0	0	0
Purchases, issuances, sales and settlements
Purchases		0	0	0	0
Issuances		0	0	0	0
Sales		0	0	0	0
Settlements		0	0	0	0
Transfers in and/or out of Level 3		0	0	0	0
Balance at end of period		0	998	0	998
Fair value option | Other investments
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance at beginning of period		22,602	67,930	27,981	67,103
Total gains or (losses) (realized/unrealized) - included in earnings	[1]	27	633	34	881
Total gains or (losses) (realized/unrealized) - included in other comprehensive income		0	0	0	0
Purchases, issuances, sales and settlements
Purchases		10,702	5,638	10,770	13,003
Issuances		0	0	0	0
Sales		0	(301)	(2,471)	(7,087)
Settlements		0	0	(2,983)	0
Transfers in and/or out of Level 3		0	0	0	0
Balance at end of period		33,331	73,900	33,331	73,900
Fair value option | Equity securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance at beginning of period		4,511	71,176	4,748	68,988
Total gains or (losses) (realized/unrealized) - included in earnings	[1]	(119)	2,502	(356)	4,690
Total gains or (losses) (realized/unrealized) - included in other comprehensive income		0	0	0	0
Purchases, issuances, sales and settlements
Purchases		0	0	0	0
Issuances		0	0	0	0
Sales		0	0	0	0
Settlements		0	0	0	0
Transfers in and/or out of Level 3		0	0	0	0
Balance at end of period		4,392	73,678	4,392	73,678
Equity securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance at beginning of period		2,768	43,112	2,918	42,015
Total gains or (losses) (realized/unrealized) - included in earnings	[1]	(89)	922	(236)	1,826
Total gains or (losses) (realized/unrealized) - included in other comprehensive income		0	0	0	0
Purchases, issuances, sales and settlements
Purchases		227	5,102	227	5,295
Issuances		0	0	0	0
Sales		0	0	(3)	0
Settlements		0	0	0	0
Transfers in and/or out of Level 3		0	0	0	0
Balance at end of period		$ 2,906	$ 49,136	$ 2,906	$ 49,136

[1] Gains or losses were included in net realized gains (losses).

[2] Includes asset backed securities, mortgage backed securities and commercial mortgage backed securities.