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	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	$ 48,023	$ 92,853
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	569	1,730
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	76,706	268,034
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	1,709	9,846
Debt Securities, Available-for-sale, Unrealized Loss Position	124,729	360,887
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	$ 2,278	$ 11,576
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Number of Positions	18	47
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Number of Positions	43	115
Debt Securities, Available-for-sale, Unrealized Loss Position, Number of Positions	61	162
Corporate Debt Securities
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	$ 18,151	$ 46,988
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	455	1,045
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	32,301	108,738
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	723	4,361
Debt Securities, Available-for-sale, Unrealized Loss Position	50,452	155,726
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	1,178	5,406
US Treasury Securities
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	0	6,138
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	0	15
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	7,167	31,693
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	48	408
Debt Securities, Available-for-sale, Unrealized Loss Position	7,167	37,831
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	48	423
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	6,173	6,478
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	107	110
Debt Securities, Available-for-sale, Unrealized Loss Position	6,173	6,478
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	107	110
US States and Political Subdivisions Debt Securities
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	29,872	33,021
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	114	522
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	29,462	113,297
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	829	4,706
Debt Securities, Available-for-sale, Unrealized Loss Position	59,334	146,318
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	943	5,228
Debt Security, Government, Non-US
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	1,603	2,835
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	2	46
Debt Securities, Available-for-sale, Unrealized Loss Position	1,603	2,835
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	$ 2	46
Collateralized Mortgage Backed Securities
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months		847
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss		37
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer		4,993
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss		215
Debt Securities, Available-for-sale, Unrealized Loss Position		5,840
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss		252
Redeemable Preferred Stock
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months		5,859
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss		111
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer		0
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss		0
Debt Securities, Available-for-sale, Unrealized Loss Position		5,859
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss		$ 111