Note 3. Investment Securities: Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value (Details) $ in Thousands	Sep. 30, 2015 USD ($)	Dec. 31, 2014 USD ($)
Available For Sale Securities Continuous Unrealized Loss Position Less Than Twelve Months Fair Value	$ 145,737	$ 161,904
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	4,056	2,540
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	71,293	161,489
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	2,710	3,736
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	217,030	323,393
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	$ 6,766	$ 6,276
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions, Less than One Year	62	70
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions, Greater than or Equal to One Year	21	46
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions	83	116
Corporate Debt Securities
Available For Sale Securities Continuous Unrealized Loss Position Less Than Twelve Months Fair Value	$ 96,293	$ 77,868
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	2,898	1,473
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	33,355	69,498
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	1,677	1,841
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	129,648	147,366
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	4,575	3,314
US Government-sponsored Enterprises Debt Securities
Available For Sale Securities Continuous Unrealized Loss Position Less Than Twelve Months Fair Value	5,604
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	125
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	5,035	9,581
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	118	86
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	10,639	9,581
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	243	86
US States and Political Subdivisions Debt Securities
Available For Sale Securities Continuous Unrealized Loss Position Less Than Twelve Months Fair Value	36,049	58,819
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	637	744
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	32,903	67,318
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	915	1,642
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	68,952	126,137
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	1,552	2,386
Redeemable Preferred Stock
Available For Sale Securities Continuous Unrealized Loss Position Less Than Twelve Months Fair Value	3,722
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	41
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	3,722
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	41
Debt Securities
Available For Sale Securities Continuous Unrealized Loss Position Less Than Twelve Months Fair Value	141,668	159,897
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	3,701	2,404
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	71,293	161,141
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	2,710	3,725
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	212,961	321,038
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	6,411	6,129
COMMON STOCK
Available For Sale Securities Continuous Unrealized Loss Position Less Than Twelve Months Fair Value	4,069	2,007
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	355	136
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value		348
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss		11
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	4,069	2,355
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	355	147
Equity Securities
Available For Sale Securities Continuous Unrealized Loss Position Less Than Twelve Months Fair Value	4,069	2,007
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	355	136
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value		348
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss		11
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	4,069	2,355
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	$ 355	147
Residential Mortgage Backed Securities Member
Available For Sale Securities Continuous Unrealized Loss Position Less Than Twelve Months Fair Value		2,062
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss		16
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value		1,562
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss		6
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value		3,624
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss		22
Commercial Mortgage Backed Securities
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value		953
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss		22
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value		953
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss		22
Foreign Government Debt
Available For Sale Securities Continuous Unrealized Loss Position Less Than Twelve Months Fair Value		21,148
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss		171
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value		12,229
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss		128
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value		33,377
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss		$ 299