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Investment Securities (Proceeds From Sales Of Securities And Components Of Investment Securities Gains And Losses) (Details) - USD ($) $ in Thousands | 12 Months Ended
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Dec. 31, 2020 | Dec. 31, 2019 | Dec. 31, 2018
Investment [Line Items] |  |  |  |
Proceeds from Sale of Available-for-sale Securities |  | $ 602,475 | $ 402,103 | $ 667,227
Proceeds from sale of equity securities |  | 2 | 3,856 | 41,637
Proceeds from sales of other securities |  | 0 | 7,244 | 0
Total proceeds | [1] | 602,477 | 413,203 | 708,864
Investment securities gains (losses), net | [1] | 11,032 | 3,626 | (488)
Available-for-sale Securities [Member] |  |  |  |
Investment [Line Items] |  |  |  |
Gains realized on sales |  | 21,096 | 2,354 | 448
Loss realized on sales |  | 0 | (2,568) | (10,101)
Other-than-temporary impairment recognized on debt securities |  | 0 | (133) | (68)
Equity securities [Member] |  |  |  |
Investment [Line Items] |  |  |  |
Gains realized on sales |  | 2 | 3,262 | 1,759
Loss realized on sales |  | 0 | 0 | (8,917)
Equity Securities, FV-NI, Unrealized Gain |  | 37 | 344 | 2,542
Other Investments [Member] |  |  |  |
Investment [Line Items] |  |  |  |
Gains realized on sales |  | 0 | 1,094 | 0
Fair value adjustments, net |  | $ (10,103) | $ (727) | $ 13,849
[1] | Available for sale debt securities, equity securities, and other securities.

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- Definition 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). + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 9 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=121645371&loc=d3e27357-111563 + Details
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