Investments in Debt and Marketable Equity Securities (and Certain Trading Assets) Disclosure [Text Block]: Realized Gain (Loss) on Investments (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Available for sale Securities Gross Realized Gain Loss Excluding Other Than Temporary Impairments	$ 2,640	$ 4,538	$ 5,203
Trading Securities, Realized Gain (Loss)	0	(409)	(1,653)
Marketable Securities, Realized Gain (Loss), Excluding Other than Temporary Impairments	2,640	4,129	3,550
Trading Securities, Change in Unrealized Holding Gain (Loss)	(102)	289	(452)
Marketable Securities, Unrealized Gain (Loss), Excluding Other than Temporary Impairments	(102)	289	(452)
Gain (Loss) on Sale of Other Investments	1	84	(4)
Gain (Loss) on Investments, Excluding Other than Temporary Impairments	2,539	4,502	3,094
Debt Securities
Available for sale Securities Gross Realized Gain Loss Excluding Other Than Temporary Impairments	2,640	4,275	3,533
COMMON STOCK, AMOUNT
Available for sale Securities Gross Realized Gain Loss Excluding Other Than Temporary Impairments	0	263	1,519
Nonredeemable Preferred Stock
Available for sale Securities Gross Realized Gain Loss Excluding Other Than Temporary Impairments	$ 0	$ 0	$ 151

This item represents the difference between the gross realized gains and losses realized on the sale of debt or equity securities categorized neither as held-to-maturity nor trading securities.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 45
-Paragraph 7
-URI http://asc.fasb.org/extlink&oid=82896770&loc=d3e26805-111562

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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.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 225
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (b)(7)
-URI http://asc.fasb.org/extlink&oid=63488584&loc=d3e20187-122688

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Amount of gain (loss) included in earnings for investments classified as other.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3602-108585

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This item represents the total realized gain (loss) included in earnings for the period as a result of selling marketable securities categorized as trading, available-for-sale, or held-to-maturity.

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This item represents the total unrealized gain (loss) included in earnings for the period as a result of holding marketable securities categorized as trading, 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.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 10
-URI http://asc.fasb.org/extlink&oid=82897076&loc=d3e27405-111563

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Amount of gain (loss) realized from securities classified as trading.

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Amount of unrealized holding gain (loss) recognized in the income statement for investments in debt and equity securities and other forms of securities that provide ownership interests classified as trading.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 225
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03.7(c))
-URI http://asc.fasb.org/extlink&oid=63488584&loc=d3e20235-122688

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 35
-Paragraph 1
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=82895926&loc=d3e24584-111560

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
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-Section 50
-Paragraph 9
-Subparagraph (e)
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