Investments in Debt and Marketable Equity Securities (and Certain Trading Assets) Disclosure [Text Block]: Debt Securities, Available-for-sale [Table Text Block] (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Debt Securities, Available-for-sale, Amortized Cost	$ 454,309	$ 448,161
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	324	1,088
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	14,556	7,337
Debt Securities, Available-for-sale	440,077	441,912
Corporate Debt Securities
Debt Securities, Available-for-sale, Amortized Cost	188,640	148,996
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	12	298
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	6,688	2,847
Debt Securities, Available-for-sale	181,964	146,447
Collateralized Mortgage Backed Securities
Debt Securities, Available-for-sale, Amortized Cost	6,464	6,857
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	0	0
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	337	180
Debt Securities, Available-for-sale	6,127	6,677
US Treasury Securities
Debt Securities, Available-for-sale, Amortized Cost	56,158	85,510
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	0	0
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	706	396
Debt Securities, Available-for-sale	55,452	85,114
US Government Agencies Debt Securities
Debt Securities, Available-for-sale, Amortized Cost	8	14
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	0	0
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	0	0
Debt Securities, Available-for-sale	8	14
US Government-sponsored Enterprises Debt Securities
Debt Securities, Available-for-sale, Amortized Cost	9,673	9,887
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	0	0
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	238	205
Debt Securities, Available-for-sale	9,435	9,682
US States and Political Subdivisions Debt Securities
Debt Securities, Available-for-sale, Amortized Cost	179,230	182,664
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	170	598
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	6,373	3,619
Debt Securities, Available-for-sale	173,027	179,643
Debt Security, Government, Non-US
Debt Securities, Available-for-sale, Amortized Cost	4,130	4,227
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	0	13
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	103	90
Debt Securities, Available-for-sale	4,027	4,150
Redeemable Preferred Stock
Debt Securities, Available-for-sale, Amortized Cost	10,006	10,006
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	142	179
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	111	0
Debt Securities, Available-for-sale	$ 10,037	$ 10,185

Amount, before tax, of unrealized gain in accumulated other comprehensive income (AOCI) on 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 50
-Paragraph 2
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=82897076&loc=d3e27161-111563

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Amount, before tax, of unrealized loss in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
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Amortized cost of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
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-Section 50
-Paragraph 2
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Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
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-Section 45
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