Other Comprehensive Income (Loss) - Amounts reclassified from accumulated other comprehensive income (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Provision for credit losses	$ (31,722)	$ (1,648)
Income tax expense	(11,619)	(38,860)
Net of tax	197,432	475,708
Reclassification out of accumulated other comprehensive income | Unrealized appreciation on available-for-sale investments
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Net realized gains (losses)	(88,640)	2,004
Provision for credit losses	(31,722)	(1,647)
Income (loss) before income taxes and income (loss) from operating affiliates	(120,362)	357
Income tax expense	18,084	(3,054)
Net of tax	$ (102,278)	$ (2,697)