Investment Securities (Proceeds From Sales Of Securities And Components Of Investment Securities Gains And Losses) (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Investment [Line Items]
Proceeds from sales of available for sale securities	$ 2,049	$ 675,870	$ 30,998
Proceeds from sales of non-marketable securities	22,331	13,161	33,444
Total proceeds	24,380	689,031	64,442
Investment securities gains (losses), net	(53)	6,320	14,124
Available-for-sale Securities [Member]
Investment [Line Items]
Gains realized on sales	109	2,925	0
Loss realized on sales	0	0	(5,197)
Gain realized on donation	0	0	1,570
Other-than-temporary impairment recognized on debt securities	(270)	(483)	(1,365)
Non-Marketable [Member]
Investment [Line Items]
Gains realized on sales	4,349	2,516	1,629
Losses realized on sales	(502)	(40)	(134)
Fair value adjustments, net	$ (3,739)	$ 1,402	$ 17,621

Fair value adjustments on non-marketable securities.

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- Definition

Gain realized on donation

+ References

No definition available.

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- Definition

Nonmarketable Securities Gain On Sale

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No definition available.

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- Definition

Nonmarketable Securities Loss On Sale

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- Definition

Proceeds from non-marketable and available for sale securities

+ References

No definition available.

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- Definition

Proceeds From Sale Of Nonmarketable Securities

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No definition available.

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- Definition

Line items represent reporting concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Article 12
-Section 12
-Sentence Column A

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- Definition

This item represents the gross profit realized on the sale of debt or equity securities categorized neither as held-to-maturity nor trading securities.

+ References

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This item represents the gross loss realized on the sale of debt or equity securities categorized neither as held-to-maturity nor trading securities.

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- Definition

This item represents the net total realized and unrealized gain (loss) included in earnings for the period as a result of selling or holding marketable securities categorized as trading, available-for-sale, or held-to-maturity, including the unrealized holding gain (loss) of held-to-maturity securities transferred to the trading security category and the cumulative unrealized gain (loss) which was included in other comprehensive income (a separate component of shareholders' equity) for available-for-sale securities transferred to trading securities during the period. Additionally, this item would include any gains (losses) realized during the period from the sale of investments accounted for under the cost method of accounting and losses recognized for other than temporary impairments (OTTI) of the subject investments.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 9
-Subparagraph (c)-(e)
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-Name Accounting Standards Codification
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-Section 45
-Paragraph 28
-URI http://asc.fasb.org/extlink&oid=66902209&loc=d3e3602-108585

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- Definition

Amount before tax of reclassification adjustment for other than temporary impairment (OTTI) related to factors other than credit loss on a previously impaired investment in available-for-sale debt security.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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-Paragraph 9A
-URI http://asc.fasb.org/extlink&oid=66010992&loc=SL6284427-111562

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- Definition

The cash inflow associated with the sale or maturity (principal being due) of securities not classified as either held-to-maturity securities or trading securities which are classified as available-for-sale securities.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
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-URI http://asc.fasb.org/extlink&oid=66902209&loc=d3e3179-108585

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-Publisher FASB
-Name Accounting Standards Codification
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-URI http://asc.fasb.org/extlink&oid=66010992&loc=d3e26853-111562

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
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