Investment Securities (Schedule of Realized Gain (Loss)) (Detail) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Investments, Debt and Equity Securities [Abstract]
Realized gains on investment securities	$ 151	$ 530	$ 647	$ 547
Realized losses on investment securities	(492)	(7)	(497)	(91)
Net realized (losses) gains on investment securities	(341)	523	150	456
Unrealized gains on equity securities with readily determinable fair value	1,647	703	1,647	2,134
Unrealized losses on equity securities with readily determinable fair value	(110)	(209)	(3,656)	(209)
Net unrealized gains (losses) on equity securities with readily determinable fair value	1,537	494	(2,009)	1,925
Upward adjustments of equity securities without readily determinable fair values	0	110	393	110
Downward adjustments of equity securities without readily determinable fair values	0	0	0	0
Impairment of equity securities without readily determinable fair values	(388)	(263)	(2,085)	(263)
Adjustment and impairment, net, of equity securities without readily determinable fair values	(388)	(153)	(1,692)	(153)
Other than temporary impairment charges (1)	0	0	0	0
Gains (losses) on investment securities, net	808	864	(3,551)	2,228
Proceeds from sales of available-for-sale securities	502,185	404,462	502,676	667,918
Proceeds from sales of equity securities with readily determinable fair value	4,000	11,000	4,030	11,000
Proceeds from sales and capital distributions of equity securities without readily determinable fair value	$ 156	$ 396	$ 444	$ 609

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

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

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The amount by which the fair value of an investment is less than the amortized cost basis or carrying amount of that investment at the balance sheet date and the decline in fair value is deemed to be other than temporary, before considering whether or not such amount is recognized in earnings or other comprehensive income.

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Amount of unrealized and realized gain (loss) on investment in marketable security, including other-than-temporary impairment (OTTI).

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Amount of cash inflow from sale of 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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Gross realized gains on marketable securities.

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Proceeds from Sales and Capital Distributions of Equity Securities Without Readily Determinable Fair Value

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Securities Owned Not Readily Marketable, Period Increase (Decrease)

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