Note 3. Investment Securities: Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended	12 Months Ended
	Mar. 31, 2014	Dec. 31, 2013
Available For Sale Securities Continuous Unrealized Loss Position Less Than Twelve Months Fair Value	$ 276,836	$ 335,792
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Aggregate Loss	8,514	14,937
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	85,628	63,529
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Aggregate Loss	4,742	5,132
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	362,464	399,321
Available-for-sale Securities, Continuous Unrealized Loss Position, Aggregate Loss	13,256	20,069
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions, Less than One Year	105	126
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions, Greater than or Equal to One Year	31	27
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions	136	153
Domestic Corporate Debt Securities
Available For Sale Securities Continuous Unrealized Loss Position Less Than Twelve Months Fair Value	101,907	124,531
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Aggregate Loss	2,689	5,340
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	36,883	21,070
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Aggregate Loss	2,297	2,127
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	138,790	145,601
Available-for-sale Securities, Continuous Unrealized Loss Position, Aggregate Loss	4,986	7,467
Residential Mortgage Backed Securities Member
Available For Sale Securities Continuous Unrealized Loss Position Less Than Twelve Months Fair Value	1,879	2,047
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Aggregate Loss	11	8
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	1,879	2,047
Available-for-sale Securities, Continuous Unrealized Loss Position, Aggregate Loss	11	8
Commercial Mortgage Backed Securities
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	869	593
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Aggregate Loss	106	382
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	869	593
Available-for-sale Securities, Continuous Unrealized Loss Position, Aggregate Loss	106	382
US Treasury Securities
Available For Sale Securities Continuous Unrealized Loss Position Less Than Twelve Months Fair Value	494	493
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Aggregate Loss	5	6
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	494	493
Available-for-sale Securities, Continuous Unrealized Loss Position, Aggregate Loss	5	6
US Government-sponsored Enterprises Debt Securities
Available For Sale Securities Continuous Unrealized Loss Position Less Than Twelve Months Fair Value	13,199	22,731
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Aggregate Loss	469	123
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	5,288	5,360
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Aggregate Loss	198	217
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	18,487	28,091
Available-for-sale Securities, Continuous Unrealized Loss Position, Aggregate Loss	667	340
US States and Political Subdivisions Debt Securities
Available For Sale Securities Continuous Unrealized Loss Position Less Than Twelve Months Fair Value	135,318	149,704
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Aggregate Loss	3,634	7,312
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	37,068	32,983
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Aggregate Loss	1,788	2,065
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	172,386	182,687
Available-for-sale Securities, Continuous Unrealized Loss Position, Aggregate Loss	5,422	9,377
Foreign Government Debt
Available For Sale Securities Continuous Unrealized Loss Position Less Than Twelve Months Fair Value	18,472	27,587
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Aggregate Loss	1,415	1,766
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	5,520	3,523
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Aggregate Loss	353	341
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	23,992	31,110
Available-for-sale Securities, Continuous Unrealized Loss Position, Aggregate Loss	1,768	2,107
Redeemable Preferred Stock
Available For Sale Securities Continuous Unrealized Loss Position Less Than Twelve Months Fair Value	3,558	3,485
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Aggregate Loss	204	278
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	3,558	3,485
Available-for-sale Securities, Continuous Unrealized Loss Position, Aggregate Loss	204	278
Debt Securities
Available For Sale Securities Continuous Unrealized Loss Position Less Than Twelve Months Fair Value	274,827	330,578
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Aggregate Loss	8,427	14,833
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	85,628	63,529
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Aggregate Loss	4,742	5,132
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	360,455	394,107
Available-for-sale Securities, Continuous Unrealized Loss Position, Aggregate Loss	13,169	19,965
COMMON STOCK
Available For Sale Securities Continuous Unrealized Loss Position Less Than Twelve Months Fair Value	2,009	2,589
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Aggregate Loss	87	70
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	2,009	2,589
Available-for-sale Securities, Continuous Unrealized Loss Position, Aggregate Loss	87	70
Equity Securities
Available For Sale Securities Continuous Unrealized Loss Position Less Than Twelve Months Fair Value	2,009	5,214
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Aggregate Loss	87	104
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	2,009	5,214
Available-for-sale Securities, Continuous Unrealized Loss Position, Aggregate Loss	87	104
Nonredeemable Preferred Stock
Available For Sale Securities Continuous Unrealized Loss Position Less Than Twelve Months Fair Value		2,625
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Aggregate Loss		34
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value		2,625
Available-for-sale Securities, Continuous Unrealized Loss Position, Aggregate Loss		$ 34