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	Mar. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	$ 54,566	$ 48,023
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	2,012	569
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	51,256	76,706
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	2,003	1,709
Debt Securities, Available-for-sale, Unrealized Loss Position	105,822	124,729
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	$ 4,015	$ 2,278
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Number of Positions	35	18
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Number of Positions	29	43
Debt Securities, Available-for-sale, Unrealized Loss Position, Number of Positions	64	61
Corporate Debt Securities
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	$ 45,248	$ 18,151
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	1,981	455
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	21,897	32,301
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	1,012	723
Debt Securities, Available-for-sale, Unrealized Loss Position	67,145	50,452
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	2,993	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	5,861	6,173
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	271	107
Debt Securities, Available-for-sale, Unrealized Loss Position	5,861	6,173
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	271	107
US States and Political Subdivisions Debt Securities
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	9,318	29,872
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	31	114
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	23,498	29,462
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	720	829
Debt Securities, Available-for-sale, Unrealized Loss Position	32,816	59,334
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	$ 751	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