Investments in Debt and Marketable Equity Securities (and Certain Trading Assets) Disclosure [Text Block]: Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value (Details) $ in Thousands	Sep. 30, 2020 USD ($)	Dec. 31, 2019 USD ($)
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	$ 75,524	$ 48,023
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	2,208	569
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	28,894	76,706
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	1,572	1,709
Debt Securities, Available-for-sale, Unrealized Loss Position	104,418	124,729
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	$ 3,780	$ 2,278
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Number of Positions	27	18
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Number of Positions	20	43
Debt Securities, Available-for-sale, Unrealized Loss Position, Number of Positions	47	61
Corporate Debt Securities
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	$ 59,414	$ 18,151
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	2,040	455
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	12,971	32,301
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	980	723
Debt Securities, Available-for-sale, Unrealized Loss Position	72,385	50,452
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	3,020	1,178
US Government-sponsored Enterprises Debt Securities
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	0	0
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	0	0
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	5,791	6,173
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	152	107
Debt Securities, Available-for-sale, Unrealized Loss Position	5,791	6,173
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	152	107
US States and Political Subdivisions Debt Securities
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	16,110	29,872
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	168	114
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	10,132	29,462
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	440	829
Debt Securities, Available-for-sale, Unrealized Loss Position	26,242	59,334
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	$ 608	943
US Treasury Securities
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months		0
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss		0
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer		7,167
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss		48
Debt Securities, Available-for-sale, Unrealized Loss Position		7,167
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss		48
Debt Security, Government, Non-US
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months		0
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss		0
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer		1,603
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss		2
Debt Securities, Available-for-sale, Unrealized Loss Position		1,603
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss		$ 2