Investment Securities Available for Sale (Summary Of Sales Transactions In The Investment Securities Available For Sale Portfolio) (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Investments [Abstract]
Proceeds from sales of investment securities available for sale	$ 35,066	$ 812,293	$ 968,606
Gross realized gains on sales	0	7,942	9,586
Gross realized losses on sales	(1,296)	(8,231)	(3,575)
Investment securities (losses) gains, net	$ (1,296)	$ (289)	$ 6,011

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).

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 45
-Paragraph 11
-URI http://asc.fasb.org/extlink&oid=109979856&loc=d3e26853-111562

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 11
-URI http://asc.fasb.org/extlink&oid=109223946&loc=d3e3151-108585

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 12
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=109223946&loc=d3e3179-108585

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Data Type:	xbrli:monetaryItemType
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