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Investment Securities (Schedule of Available-for-Sale Investment Securities Gross Gains and Gross Losses Realized) (Detail) - USD ($) | 3 Months Ended
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Mar. 31, 2022 | Mar. 31, 2021
Investments, Debt and Equity Securities [Abstract] |  |
Realized gains on investment securities | $ 258,000 | $ 216,000
Realized losses on investment securities | (8,000) | (6,000)
Net realized gains on investment securities | 250,000 | 210,000
Unrealized gains on equity securities with readily determinable fair value | 180,000 | 1,875,000
Unrealized losses on equity securities with readily determinable fair value | (2,641,000) | (901,000)
Net unrealized (losses) gains on equity securities with readily determinable fair value | (2,461,000) | 974,000
Upward adjustments of equity securities without readily determinable fair values | 0 | 0
Downward adjustments of equity securities without readily determinable fair values | 0 | 0
Impairment of equity securities without readily determinable fair values | (571,000) | (30,000)
Adjustment and impairment, net, of equity securities without readily determinable fair values | (571,000) | (30,000)
(Losses) gains on investment securities, net | (2,782,000) | 1,154,000
Proceeds from sales of available-for-sale securities | 0 | 0
Proceeds from sales of equity securities with readily determinable fair value | 18,753,000 | 1,509,000
Proceeds from sales and capital distributions of equity securities without readily determinable fair value | $ 250,000 | $ 386,000

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- Definition Amount of unrealized gain 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/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 321 -SubTopic 10 -Section 50 -Paragraph 4 -URI http://asc.fasb.org/extlink&oid=123583765&loc=SL75117546-209714 + Details
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- Definition 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). + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 220 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-04(3)(d)) -URI http://asc.fasb.org/extlink&oid=120400993&loc=SL114874131-224263 Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 321 -SubTopic 10 -Section 50 -Paragraph 4 -URI http://asc.fasb.org/extlink&oid=123583765&loc=SL75117546-209714 + Details
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- Definition Amount of impairment loss on investment in equity security without readily determinable fair value. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 321 -SubTopic 10 -Section 50 -Paragraph 3 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=123583765&loc=SL75117539-209714 + Details
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