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Securities Fair Value Option Securities (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Fair Value Option Securities [Line Items]
Fair value option securities	$ 114,982	$ 1,098,577
Fair Value Option Securities Unrealized Gain or Loss	4,463	14,061
U.S. Treasury [Member]
Fair Value Option Securities [Line Items]
Fair value option securities	0	9,917
Fair Value Option Securities Unrealized Gain or Loss	0	(48)
Residential agency mortgage-backed securities [Member]
Fair Value Option Securities [Line Items]
Fair value option securities	114,982	1,088,660
Fair Value Option Securities Unrealized Gain or Loss	$ 4,463	$ 14,109

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- Definition

Fair value option securities represent securities the Company has elected to carry at fair value and separately identified on the balance sheet with changes in fair value recognized in earnings as they occur. Certain residential mortgage-backed securities issued by US government agencies are held as an economic hedge of changes in the fair value of mortgage servicing rights and related derivative contracts. In addition, other securities may be held to manage interest rate risk or for deferred compensation purposes. Securities held for interest rate risk management may be economically hedged by derivative contracts not designated as hedging instruments effectively modify these fixed rate securities into variable rate securities.

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- Definition

[Line Items] for Fair Value Option Securities [Table]

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- Definition

Fair Value Option Securities Net Unrealized Gain or Loss

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