Investments in Equity Securities (Investments in Equity Securities Available for Sale) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Fair Value
Debt Securities, Available-for-sale [Line Items]
Cost	$ 949,332	$ 1,115,328
Gross unrealized gains	194,881	193,218
Gross unrealized losses	(53,866)	(122,652)
Equity securities	1,090,347	1,185,894
Fair Value | Common stocks
Debt Securities, Available-for-sale [Line Items]
Cost	664,997	855,987
Gross unrealized gains	191,806	192,165
Gross unrealized losses	(18,749)	(65,401)
Equity securities	838,054	982,751
Fair Value | Preferred stocks
Debt Securities, Available-for-sale [Line Items]
Cost	284,335	259,341
Gross unrealized gains	3,075	1,053
Gross unrealized losses	(35,117)	(57,251)
Equity securities	252,293	203,143
Carrying Value
Debt Securities, Available-for-sale [Line Items]
Equity securities	1,090,347	1,185,894
Carrying Value | Common stocks
Debt Securities, Available-for-sale [Line Items]
Equity securities	838,054	982,751
Carrying Value | Preferred stocks
Debt Securities, Available-for-sale [Line Items]
Equity securities	$ 252,293	$ 203,143