Accumulated Other Comprehensive Income (Loss) - Components of AOCI (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	$ 6,461,697	$ 5,609,482	$ 5,984,612	$ 5,837,218
Other comprehensive loss	(93,445)	(199,384)	(109,748)	(709,651)
Ending balance	6,596,706	5,660,668	6,596,706	5,660,668
Debt Securities
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(681,536)	(554,781)	(694,815)	(85,703)
Net unrealized (losses) gains arising during the period	(72,691)	(161,445)	(72,034)	(635,664)
Amounts reclassified from AOCI	2,870	3,256	15,492	8,397
Other comprehensive loss	(69,821)	(158,189)	(56,542)	(627,267)
Ending balance	(751,357)	(712,970)	(751,357)	(712,970)
Cash Flow Hedges
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(74,805)	(30,846)	(49,531)	257
Net unrealized (losses) gains arising during the period	(44,347)	(34,423)	(91,468)	(63,232)
Amounts reclassified from AOCI	17,013	1,154	38,860	(1,140)
Other comprehensive loss	(27,334)	(33,269)	(52,608)	(64,372)
Ending balance	(102,139)	(64,115)	(102,139)	(64,115)
Foreign Currency Translation Adjustments
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(25,591)	(15,021)	(21,283)	(4,935)
Net unrealized (losses) gains arising during the period	3,710	(7,926)	(598)	(18,012)
Amounts reclassified from AOCI	0	0	0	0
Other comprehensive loss	3,710	(7,926)	(598)	(18,012)
Ending balance	(21,881)	(22,947)	(21,881)	(22,947)
AOCI, Net of Tax
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(781,932)	(600,648)	(765,629)	(90,381)
Net unrealized (losses) gains arising during the period	(113,328)	(203,794)	(164,100)	(716,908)
Amounts reclassified from AOCI	19,883	4,410	54,352	7,257
Other comprehensive loss	(93,445)	(199,384)	(109,748)	(709,651)
Ending balance	$ (875,377)	$ (800,032)	$ (875,377)	$ (800,032)