Note 3. Investment Securities: Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value (Details) (USD $) In Thousands, unless otherwise specified	9 Months Ended	12 Months Ended
	Sep. 30, 2014	Dec. 31, 2013
Available For Sale Securities Continuous Unrealized Loss Position Less Than Twelve Months Fair Value	$ 207,068	$ 335,792
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Aggregate Loss	2,828	14,937
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	201,006	63,529
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Aggregate Loss	5,956	5,132
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	408,074	399,321
Available-for-sale Securities, Continuous Unrealized Loss Position, Aggregate Loss	8,784	20,069
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions, Less than One Year	76	126
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions, Greater than or Equal to One Year	65	27
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions	141	153
Domestic Corporate Debt Securities
Available For Sale Securities Continuous Unrealized Loss Position Less Than Twelve Months Fair Value	107,877	124,531
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Aggregate Loss	1,754	5,340
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	83,832	21,070
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Aggregate Loss	2,938	2,127
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	191,709	145,601
Available-for-sale Securities, Continuous Unrealized Loss Position, Aggregate Loss	4,692	7,467
Residential Mortgage Backed Securities Member
Available For Sale Securities Continuous Unrealized Loss Position Less Than Twelve Months Fair Value	1,657	2,047
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Aggregate Loss	13	8
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	1,657	2,047
Available-for-sale Securities, Continuous Unrealized Loss Position, Aggregate Loss	13	8
Commercial Mortgage Backed Securities
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	924	593
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Aggregate Loss	51	382
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	924	593
Available-for-sale Securities, Continuous Unrealized Loss Position, Aggregate Loss	51	382
US Government-sponsored Enterprises Debt Securities
Available For Sale Securities Continuous Unrealized Loss Position Less Than Twelve Months Fair Value	9,164	22,731
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Aggregate Loss	80	123
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	2,516	5,360
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Aggregate Loss	70	217
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	11,680	28,091
Available-for-sale Securities, Continuous Unrealized Loss Position, Aggregate Loss	150	340
US States and Political Subdivisions Debt Securities
Available For Sale Securities Continuous Unrealized Loss Position Less Than Twelve Months Fair Value	59,372	149,704
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Aggregate Loss	627	7,312
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	95,235	32,983
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Aggregate Loss	2,390	2,065
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	154,607	182,687
Available-for-sale Securities, Continuous Unrealized Loss Position, Aggregate Loss	3,017	9,377
Foreign Government Debt
Available For Sale Securities Continuous Unrealized Loss Position Less Than Twelve Months Fair Value	21,238	27,587
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Aggregate Loss	187	1,766
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	18,499	3,523
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Aggregate Loss	507	341
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	39,737	31,110
Available-for-sale Securities, Continuous Unrealized Loss Position, Aggregate Loss	694	2,107
Redeemable Preferred Stock
Available For Sale Securities Continuous Unrealized Loss Position Less Than Twelve Months Fair Value	3,743	3,485
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Aggregate Loss	19	278
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	3,743	3,485
Available-for-sale Securities, Continuous Unrealized Loss Position, Aggregate Loss	19	278
Debt Securities
Available For Sale Securities Continuous Unrealized Loss Position Less Than Twelve Months Fair Value	203,051	330,578
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Aggregate Loss	2,680	14,833
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	201,006	63,529
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Aggregate Loss	5,956	5,132
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	404,057	394,107
Available-for-sale Securities, Continuous Unrealized Loss Position, Aggregate Loss	8,636	19,965
COMMON STOCK
Available For Sale Securities Continuous Unrealized Loss Position Less Than Twelve Months Fair Value	2,610	2,589
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Aggregate Loss	145	70
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	2,610	2,589
Available-for-sale Securities, Continuous Unrealized Loss Position, Aggregate Loss	145	70
Nonredeemable Preferred Stock
Available For Sale Securities Continuous Unrealized Loss Position Less Than Twelve Months Fair Value	1,407	2,625
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Aggregate Loss	3	34
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	1,407	2,625
Available-for-sale Securities, Continuous Unrealized Loss Position, Aggregate Loss	3	34
Equity Securities
Available For Sale Securities Continuous Unrealized Loss Position Less Than Twelve Months Fair Value	4,017	5,214
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Aggregate Loss	148	104
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	4,017	5,214
Available-for-sale Securities, Continuous Unrealized Loss Position, Aggregate Loss	148	104
US Treasury Securities
Available For Sale Securities Continuous Unrealized Loss Position Less Than Twelve Months Fair Value		493
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Aggregate Loss		6
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value		493
Available-for-sale Securities, Continuous Unrealized Loss Position, Aggregate Loss		$ 6