Note 2: Investments in Securities: Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	$ 0	$ 11,255
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	0	(82)
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	24,762	74,186
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(265)	(2,489)
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	24,762	85,441
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	(265)	(2,571)
Collateralized Mortgage Obligations
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	69,372	9,725
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(921)	(14)
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	0	0
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	0	0
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	69,372	9,725
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	(921)	(14)
Small Business Administration securities
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	22,058
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(74)
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	0
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	0
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	22,058
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	(74)
US States and Political Subdivisions Debt Securities
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	0	511
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	0	0
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	0	0
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	0	0
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	0	511
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	0	0
Unrealized Losses, Fair Value, Time in Continuous Unrealized Loss Position
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	91,430	21,491
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(995)	(96)
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	24,762	74,186
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(265)	(2,489)
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	116,192	95,677
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	$ (1,260)	$ (2,585)