Fair Value of Assets & Liabilities - Summary Of Changes In Level 3 Assets And Liabilities Measured At Fair Value (Details) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2020	Mar. 31, 2019
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Beginning balance	$ (22,795)	$ (31,540)
Net income	(511)	135
Purchases	0	0
Sales	0	0
Settlements	2,416	2,435
Net transfers into/(out of) Level 3	0	0
Ending balance	(20,890)	(28,970)
Net unrealized gains/(losses) included in net income	(511)	135
Trading securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	941	1,524
Net income	(156)	21
Purchases	0	0
Sales	0	0
Settlements	0	(148)
Net transfers into/(out of) Level 3	0	0
Ending balance	785	1,397
Net unrealized gains/(losses) included in net income	0	(30)
Interest- only strips- AFS
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	19,136	9,902
Net income	(1,295)	(1,258)
Purchases	5,481	86
Sales	(8,703)	(13,012)
Settlements	0	0
Net transfers into/(out of) Level 3	8,485	17,477
Ending balance	23,104	13,195
Net unrealized gains/(losses) included in net income	(865)	(894)
Loans held- for-sale
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	14,033	16,273
Net income	329	495
Purchases	0	0
Sales	0	0
Settlements	(778)	(1,017)
Net transfers into/(out of) Level 3	0	0
Ending balance	13,584	15,751
Net unrealized gains/(losses) included in net income	$ 329	$ 495

Amount of unrealized gain (loss) recognized in income from asset measured at fair value on recurring basis using unobservable input (level 3) and still held.

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Amount of purchases of financial instrument classified as an asset measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.

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Amount of transfer of financial instrument classified as an asset into (out of) level 3 of the fair value hierarchy.

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Amount of unrealized gain (loss) recognized in income for derivative asset (liability) after deduction of derivative liability (asset), measured at fair value using unobservable input (level 3) and still held.

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Amount of gain (loss) recognized in income from derivative asset (liability) after deduction of derivative liability (asset), measured at fair value on recurring basis using unobservable input (level 3).

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Amount of purchases of financial instrument classified as a derivative asset (liability) after deduction of derivative liability (asset), measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.

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Amount of sales of financial instrument classified as a derivative asset (liability) after deduction of derivative liability (asset), measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.

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Amount of settlements of financial instrument classified as a derivative asset (liability) after deduction of derivative liability, measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.

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Amount of transfers of financial instrument classified as a derivative asset (liability) after deduction of derivative liability (asset) into (out of) level 3 of the fair value hierarchy.

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