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Securities, Gains and (Losses) on Equity Securities (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2020 USD ($) Issuer	Dec. 31, 2019 USD ($) Issuer
Gains (losses) on equity securities [Abstract]
Net (losses) and gains recognized on equity securities	$ (414)	$ 4,280
Less: Net gains recognized during the period on equity securities sold during the period	0	3,966
Unrealized (losses) and gains recognized on equity securities still held	(414)	314
Equity Securities without Readily Determinable Fair Value, Annual Amount [Abstract]
Carrying amount of equity securities without readily determinable fair values	2,000	4,000
Impairment adjustments of equity securities without readily determinable fair values	0	0
Downward adjustments of equity securities without readily determinable fair values	0	0
Upward adjustments of equity securities without readily determinable fair values	$ 0	$ 0
Number of issuers whose holdings exceeded 10% of consolidated stockholders' equity, excluding U.S. Government securities | Issuer	0	0
Visa Class B Common Stock [Member]
Equity Securities without Readily Determinable Fair Value, Annual Amount [Abstract]
Gain from sale of equity securities without readily determinable fair value		$ 4,000

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Amount of realized gain from sale of investment in equity security without readily determinable fair value.

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Amount of unrealized and realized gain (loss) on investment in equity security measured at fair value with change in fair value recognized in net income (FV-NI).

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 321
-SubTopic 10
-Section 50
-Paragraph 4
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Amount of realized gain (loss) from sale of investment in equity security measured at fair value with change in fair value recognized in net income (FV-NI).

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 321
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