Fair Value Disclosures [Text Block]: Fair Value, Assets Measured on Recurring Basis (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Available-for-sale Securities, Debt Securities	$ 426,000	$ 449,487
Available-for-sale Securities, Equity Securities	5,460	5,333
Trading Securities	516	592
Corporate Debt Securities
Available-for-sale Securities, Debt Securities	158,176	187,695
Residential Mortgage Backed Securities
Available-for-sale Securities, Debt Securities	6,905	5,913
US Treasury Securities
Available-for-sale Securities, Debt Securities	43,877	43,109
US Government Agencies Debt Securities
Available-for-sale Securities, Debt Securities	16	23
US Government-sponsored Enterprises Debt Securities
Available-for-sale Securities, Debt Securities	9,782	9,880
US States and Political Subdivisions Debt Securities
Available-for-sale Securities, Debt Securities	193,039	186,811
Foreign Government Debt
Available-for-sale Securities, Debt Securities	4,213	4,954
Redeemable Preferred Stock
Available-for-sale Securities, Debt Securities	9,992	11,102
Common Stock
Available-for-sale Securities, Equity Securities	1,785	1,790
Nonredeemable Preferred Stock
Available-for-sale Securities, Equity Securities	3,675	3,543
Fair Value, Measurements, Recurring
Available-for-sale Securities, Debt Securities	426,000	449,487
Available-for-sale Securities, Equity Securities	5,460	5,333
Trading Securities	516	592
Assets, Fair Value Disclosure, Recurring	431,976	455,412
Fair Value, Measurements, Recurring | Corporate Debt Securities
Available-for-sale Securities, Debt Securities	158,176	187,695
Fair Value, Measurements, Recurring | Residential Mortgage Backed Securities
Available-for-sale Securities, Debt Securities	6,905	5,913
Fair Value, Measurements, Recurring | US Treasury Securities
Available-for-sale Securities, Debt Securities	43,877	43,109
Fair Value, Measurements, Recurring | US Government Agencies Debt Securities
Available-for-sale Securities, Debt Securities	16	23
Fair Value, Measurements, Recurring | US Government-sponsored Enterprises Debt Securities
Available-for-sale Securities, Debt Securities	9,782	9,880
Fair Value, Measurements, Recurring | US States and Political Subdivisions Debt Securities
Available-for-sale Securities, Debt Securities	193,041	186,811
Fair Value, Measurements, Recurring | Foreign Government Debt
Available-for-sale Securities, Debt Securities	4,213	4,954
Fair Value, Measurements, Recurring | Redeemable Preferred Stock
Available-for-sale Securities, Debt Securities	9,990	11,102
Fair Value, Measurements, Recurring | Common Stock
Available-for-sale Securities, Equity Securities	1,785	1,790
Fair Value, Measurements, Recurring | Nonredeemable Preferred Stock
Available-for-sale Securities, Equity Securities	3,675	3,543
Fair Value, Measurements, Recurring | Equity Securities
Trading Securities	516	592
Fair Value, Inputs, Level 1 | Fair Value, Measurements, Recurring
Available-for-sale Securities, Debt Securities	9,990	11,102
Available-for-sale Securities, Equity Securities	5,460	5,333
Trading Securities	516	592
Assets, Fair Value Disclosure, Recurring	15,966	17,027
Fair Value, Inputs, Level 1 | Fair Value, Measurements, Recurring | Corporate Debt Securities
Available-for-sale Securities, Debt Securities	0	0
Fair Value, Inputs, Level 1 | Fair Value, Measurements, Recurring | Residential Mortgage Backed Securities
Available-for-sale Securities, Debt Securities	0	0
Fair Value, Inputs, Level 1 | Fair Value, Measurements, Recurring | US Treasury Securities
Available-for-sale Securities, Debt Securities	0	0
Fair Value, Inputs, Level 1 | Fair Value, Measurements, Recurring | US Government Agencies Debt Securities
Available-for-sale Securities, Debt Securities	0	0
Fair Value, Inputs, Level 1 | Fair Value, Measurements, Recurring | US Government-sponsored Enterprises Debt Securities
Available-for-sale Securities, Debt Securities	0	0
Fair Value, Inputs, Level 1 | Fair Value, Measurements, Recurring | US States and Political Subdivisions Debt Securities
Available-for-sale Securities, Debt Securities	0	0
Fair Value, Inputs, Level 1 | Fair Value, Measurements, Recurring | Foreign Government Debt
Available-for-sale Securities, Debt Securities	0	0
Fair Value, Inputs, Level 1 | Fair Value, Measurements, Recurring | Redeemable Preferred Stock
Available-for-sale Securities, Debt Securities	9,990	11,102
Fair Value, Inputs, Level 1 | Fair Value, Measurements, Recurring | Common Stock
Available-for-sale Securities, Equity Securities	1,785	1,790
Fair Value, Inputs, Level 1 | Fair Value, Measurements, Recurring | Nonredeemable Preferred Stock
Available-for-sale Securities, Equity Securities	3,675	3,543
Fair Value, Inputs, Level 1 | Fair Value, Measurements, Recurring | Equity Securities
Trading Securities	516	592
Fair Value, Inputs, Level 2 | Fair Value, Measurements, Recurring
Available-for-sale Securities, Debt Securities	414,093	436,352
Available-for-sale Securities, Equity Securities	0	0
Trading Securities	0	0
Assets, Fair Value Disclosure, Recurring	414,093	436,352
Fair Value, Inputs, Level 2 | Fair Value, Measurements, Recurring | Corporate Debt Securities
Available-for-sale Securities, Debt Securities	158,176	187,695
Fair Value, Inputs, Level 2 | Fair Value, Measurements, Recurring | Residential Mortgage Backed Securities
Available-for-sale Securities, Debt Securities	6,905	5,913
Fair Value, Inputs, Level 2 | Fair Value, Measurements, Recurring | US Treasury Securities
Available-for-sale Securities, Debt Securities	43,877	43,109
Fair Value, Inputs, Level 2 | Fair Value, Measurements, Recurring | US Government Agencies Debt Securities
Available-for-sale Securities, Debt Securities	16	23
Fair Value, Inputs, Level 2 | Fair Value, Measurements, Recurring | US Government-sponsored Enterprises Debt Securities
Available-for-sale Securities, Debt Securities	9,782	9,880
Fair Value, Inputs, Level 2 | Fair Value, Measurements, Recurring | US States and Political Subdivisions Debt Securities
Available-for-sale Securities, Debt Securities	191,124	184,778
Fair Value, Inputs, Level 2 | Fair Value, Measurements, Recurring | Foreign Government Debt
Available-for-sale Securities, Debt Securities	4,213	4,954
Fair Value, Inputs, Level 2 | Fair Value, Measurements, Recurring | Redeemable Preferred Stock
Available-for-sale Securities, Debt Securities	0	0
Fair Value, Inputs, Level 2 | Fair Value, Measurements, Recurring | Common Stock
Available-for-sale Securities, Equity Securities	0	0
Fair Value, Inputs, Level 2 | Fair Value, Measurements, Recurring | Nonredeemable Preferred Stock
Available-for-sale Securities, Equity Securities	0	0
Fair Value, Inputs, Level 2 | Fair Value, Measurements, Recurring | Equity Securities
Trading Securities	0	0
Fair Value, Inputs, Level 3 | Fair Value, Measurements, Recurring
Available-for-sale Securities, Debt Securities	1,917	2,033
Available-for-sale Securities, Equity Securities	0	0
Trading Securities	0	0
Assets, Fair Value Disclosure, Recurring	1,917	2,033
Fair Value, Inputs, Level 3 | Fair Value, Measurements, Recurring | Corporate Debt Securities
Available-for-sale Securities, Debt Securities	0	0
Fair Value, Inputs, Level 3 | Fair Value, Measurements, Recurring | Residential Mortgage Backed Securities
Available-for-sale Securities, Debt Securities	0	0
Fair Value, Inputs, Level 3 | Fair Value, Measurements, Recurring | US Treasury Securities
Available-for-sale Securities, Debt Securities	0	0
Fair Value, Inputs, Level 3 | Fair Value, Measurements, Recurring | US Government Agencies Debt Securities
Available-for-sale Securities, Debt Securities	0	0
Fair Value, Inputs, Level 3 | Fair Value, Measurements, Recurring | US Government-sponsored Enterprises Debt Securities
Available-for-sale Securities, Debt Securities	0	0
Fair Value, Inputs, Level 3 | Fair Value, Measurements, Recurring | US States and Political Subdivisions Debt Securities
Available-for-sale Securities, Debt Securities	1,917	2,033
Fair Value, Inputs, Level 3 | Fair Value, Measurements, Recurring | Foreign Government Debt
Available-for-sale Securities, Debt Securities	0	0
Fair Value, Inputs, Level 3 | Fair Value, Measurements, Recurring | Redeemable Preferred Stock
Available-for-sale Securities, Debt Securities	0	0
Fair Value, Inputs, Level 3 | Fair Value, Measurements, Recurring | Common Stock
Available-for-sale Securities, Equity Securities	0	0
Fair Value, Inputs, Level 3 | Fair Value, Measurements, Recurring | Nonredeemable Preferred Stock
Available-for-sale Securities, Equity Securities	0	0
Fair Value, Inputs, Level 3 | Fair Value, Measurements, Recurring | Equity Securities
Trading Securities	$ 0	$ 0