Accumulated Other Comprehensive Income (Loss) - Components of AOCI (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	$ 5,837,218	$ 5,269,175	$ 5,017,617
Other comprehensive (loss) income	(675,248)	(134,706)	62,733
Ending balance	5,984,612	5,837,218	5,269,175
Debt Securities
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(85,703)	52,247	(2,419)
Net unrealized gains (losses) arising during the period	(620,870)	(136,846)	63,329
Amounts reclassified from AOCI	11,758	(1,104)	(8,663)
Other comprehensive (loss) income	(609,112)	(137,950)	54,666
Ending balance	(694,815)	(85,703)	52,247
Cash Flow Hedges
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	257	(1,230)	0
Net unrealized gains (losses) arising during the period	(52,623)	866	(1,149)
Amounts reclassified from AOCI	2,835	621	(81)
Other comprehensive (loss) income	(49,788)	1,487	(1,230)
Ending balance	(49,531)	257	(1,230)
Foreign Currency Translation Adjustments
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(4,935)	(6,692)	(15,989)
Net unrealized gains (losses) arising during the period	(16,348)	1,757	9,297
Amounts reclassified from AOCI	0	0	0
Other comprehensive (loss) income	(16,348)	1,757	9,297
Ending balance	(21,283)	(4,935)	(6,692)
Total
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(90,381)	44,325	(18,408)
Net unrealized gains (losses) arising during the period	(689,841)	(134,223)	71,477
Amounts reclassified from AOCI	14,593	(483)	(8,744)
Other comprehensive (loss) income	(675,248)	(134,706)	62,733
Ending balance	$ (765,629)	$ (90,381)	$ 44,325