Fair Value Disclosures [Text Block]: Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Table Text Block] (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value	$ 2,033	$ 3,374
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Other Comprehensive Income (Loss)	(35)	(336)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Settlements	(122)	(180)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Sales	0	(966)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value	1,876	2,033
Net realized investment gains
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings	0	141
US States and Political Subdivisions Debt Securities
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value	2,033	2,179
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Other Comprehensive Income (Loss)	(35)	(40)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Settlements	(122)	(106)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Sales	0	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value	1,876	2,033
US States and Political Subdivisions Debt Securities | Net realized investment gains
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings	0	0
Commercial Mortgage Backed Securities
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value	$ 0	1,195
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Other Comprehensive Income (Loss)		(296)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Settlements		(74)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Sales		(966)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value		0
Commercial Mortgage Backed Securities | Net realized investment gains
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings		$ 141