Investments Securities - Schedule of Investments in Debt Securities (Details) - USD ($) $ in Thousands	Jun. 30, 2024	Dec. 31, 2023
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	$ 1,443,344	$ 596,757
Accrued Interest	$ 3,039	639
Debt Securities, Available-for-Sale, Accrued Interest, after Allowance for Credit Loss, Statement of Financial Position [Extensible Enumeration]	Fair Value
Gross Unrealized Gains	$ 3,440	1,011
Gross Unrealized Losses	(5,600)	(3,220)
Fair Value	$ 1,444,223	$ 595,187
Percentage of high credit quality on amortized cost basis of investments	98.00%	92.00%
U.S. Treasury securities
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	$ 206,022	$ 518,673
Accrued Interest	66	206
Gross Unrealized Gains	0	978
Gross Unrealized Losses	(402)	(780)
Fair Value	205,686	519,077
Multinational securities
Debt Securities, Available-for-sale [Line Items]
Amortized Cost		8,548
Accrued Interest		103
Gross Unrealized Gains		0
Gross Unrealized Losses		(17)
Fair Value		8,634
Corporate bonds
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	18,594	32,609
Accrued Interest	127	207
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(663)	(1,092)
Fair Value	18,058	31,724
Agency mortgage-backed securities
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	1,214,366	28,714
Accrued Interest	2,837	111
Gross Unrealized Gains	3,440	33
Gross Unrealized Losses	(4,304)	(1,016)
Fair Value	1,216,339	27,842
Other asset-backed securities
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	3,418	7,272
Accrued Interest	1	4
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(53)	(154)
Fair Value	3,366	7,122
Other
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	944	941
Accrued Interest	8	8
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(178)	(161)
Fair Value	$ 774	$ 788