Investments - Schedule of Aggregated Income Statement Summarized Financial Information for Partnerships in our Alternative Investment Portfolio (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Schedule of Equity Method Investments [Line Items]
Net investment income earned	$ 108,642	$ 97,696	$ 216,491	$ 189,202
Investments Accounted For Under The Equity Method
Schedule of Equity Method Investments [Line Items]
Net investment income (loss)	242,400	(70,600)	(103,600)	(141,300)
Realized gains	1,554,200	922,000	3,385,100	2,644,300
Net change in unrealized appreciation (depreciation)	2,850,200	3,754,000	6,669,200	5,197,800
Net income	4,646,800	4,605,400	9,950,700	7,700,800
Alternative investments
Schedule of Equity Method Investments [Line Items]
Net investment income earned	$ 10,517	$ 11,396	$ 17,398	$ 19,164