Securities - Schedule of Components of Investment Securities Gains, Net (Detail) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Available-for-sale debt securities:
Gains realized on sales	$ 1,300	$ 4,177	$ 4,020	$ 5,404
Losses realized on sales		(171)		(171)
Equity securities with readily determinable fair values:
Fair value adjustments, net	8,738		(5,180)
Equity securities without readily determinable fair values:
Fair value adjustments, net	5,417	573	8,279	2,866
Total investment securities gains, net	$ 15,455	$ 4,579	$ 7,119	$ 8,099

Equity securities with out readily determinable fair values adjustments net.

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Amount of unrealized and realized gain (loss) on investment in debt and equity securities.

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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
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Amount of realized gain on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
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Amount of realized loss on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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