Investment Securities (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2023	Dec. 31, 2022
Cost
Equity	$ 324,488	$ 323,907
Debt	830,095	833,035
Other	9,885	10,445
Total	1,164,468	1,167,387
Gains
Equity	191,858	159,445
Debt	1,698	372
Other	30	20
Total	193,586	159,837
Losses
Equity	(7,030)	(8,949)
Debt	(34,803)	(46,369)
Other	(26)	(9)
Total	(41,859)	(55,327)
Fair Value
Equity	509,316	474,403
Debt	796,990	787,038
Other	9,889	10,456
Total	$ 1,316,195	$ 1,271,897