Accumulated Other Comprehensive Income (Loss) - Components of AOCI (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2022	Mar. 31, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	$ 5,703,456	$ 5,837,218	$ 5,285,027	$ 5,837,218	$ 5,269,175
Other comprehensive (loss) income	(205,723)		75,351	(510,267)	(59,014)
Ending balance	5,609,482	5,703,456	5,547,548	5,609,482	5,547,548
Net changes in unrealized gains (losses) on securities transferred from AFS to HTM		113,000
Debt Securities
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(365,653)	(85,703)	(81,201)	(85,703)	52,247
Net unrealized gains (losses) arising during the period	(192,858)		73,494	(474,219)	(59,819)
Amounts reclassified from AOCI	3,730		(445)	5,141	(580)
Other comprehensive (loss) income	(189,128)		73,049	(469,078)	(60,399)
Ending balance	(554,781)	(365,653)	(8,152)	(554,781)	(8,152)
Net changes in unrealized gains (losses) on securities transferred from AFS to HTM	(3,750)		0	(6,061)	0
Cash Flow Hedges
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(24,466)	257	(798)	257	(1,230)
Net unrealized gains (losses) arising during the period	(5,582)		(76)	(28,809)	229
Amounts reclassified from AOCI	(798)		144	(2,294)	271
Other comprehensive (loss) income	(6,380)		68	(31,103)	500
Ending balance	(30,846)	(24,466)	(730)	(30,846)	(730)
Foreign Currency Translation Adjustments
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(4,806)	(4,935)	(8,041)	(4,935)	(6,692)
Net unrealized gains (losses) arising during the period	(10,215)		2,234	(10,086)	885
Amounts reclassified from AOCI	0		0	0	0
Other comprehensive (loss) income	(10,215)		2,234	(10,086)	885
Ending balance	(15,021)	(4,806)	(5,807)	(15,021)	(5,807)
AOCI, Net of Tax
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(394,925)	(90,381)	(90,040)	(90,381)	44,325
Net unrealized gains (losses) arising during the period	(208,655)		75,652	(513,114)	(58,705)
Amounts reclassified from AOCI	2,932		(301)	2,847	(309)
Other comprehensive (loss) income	(205,723)		75,351	(510,267)	(59,014)
Ending balance	$ (600,648)	$ (394,925)	$ (14,689)	$ (600,648)	$ (14,689)

A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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Amount after tax, before reclassification adjustments, of other comprehensive income (loss), attributable to parent.

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Amount, after tax, of adjustment from accumulated other comprehensive income (loss) for amortization of gain (loss) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale) from transfer to investment in debt security measured at amortized cost (held-to-maturity).

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Amount after tax of other comprehensive income (loss) attributable to parent entity.

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Total of all stockholders' equity (deficit) items, net of receivables from officers, directors, owners, and affiliates of the entity which are attributable to the parent. The amount of the economic entity's stockholders' equity attributable to the parent excludes the amount of stockholders' equity which is allocable to that ownership interest in subsidiary equity which is not attributable to the parent (noncontrolling interest, minority interest). This excludes temporary equity and is sometimes called permanent equity.

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