Note 2. Investment Securities: Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Available For Sale Securities Continuous Unrealized Loss Position Less Than Twelve Months Fair Value	$ 161,904	$ 335,792
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	2,540	14,937
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	161,489	63,529
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	3,736	5,132
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	323,393	399,321
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	6,276	20,069
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions, Less than One Year	70	126
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions, Greater than or Equal to One Year	46	27
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions	116	153
Corporate Debt Securities
Available For Sale Securities Continuous Unrealized Loss Position Less Than Twelve Months Fair Value	77,868	124,531
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	1,473	5,340
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	69,498	21,070
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	1,841	2,127
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	147,366	145,601
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	3,314	7,467
Residential Mortgage Backed Securities Member
Available For Sale Securities Continuous Unrealized Loss Position Less Than Twelve Months Fair Value	2,062	2,047
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	16	8
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	2,047
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	22	8
Commercial Mortgage Backed Securities
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	953	593
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	22	382
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	953	593
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	22	382
US Government-sponsored Enterprises Debt Securities
Available For Sale Securities Continuous Unrealized Loss Position Less Than Twelve Months Fair Value		22,731
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss		123
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	9,581	5,360
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	86	217
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	9,581	28,091
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	86	340
US States and Political Subdivisions Debt Securities
Available For Sale Securities Continuous Unrealized Loss Position Less Than Twelve Months Fair Value	58,819	149,704
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	744	7,312
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	67,318	32,983
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	1,642	2,065
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	126,137	182,687
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	2,386	9,377
Foreign Government Debt
Available For Sale Securities Continuous Unrealized Loss Position Less Than Twelve Months Fair Value	21,148	27,587
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	171	1,766
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	12,229	3,523
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	128	341
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	33,377	31,110
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	299	2,107
Debt Securities
Available For Sale Securities Continuous Unrealized Loss Position Less Than Twelve Months Fair Value	159,897	330,578
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	2,404	14,833
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	161,141	63,529
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	3,725	5,132
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	321,038	394,107
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	6,129	19,965
COMMON STOCK
Available For Sale Securities Continuous Unrealized Loss Position Less Than Twelve Months Fair Value	2,007	2,589
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	136	70
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	2,355	2,589
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	147	70
Equity Securities
Available For Sale Securities Continuous Unrealized Loss Position Less Than Twelve Months Fair Value	2,007	5,214
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	136	104
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	2,355	5,214
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	147	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, Accumulated Loss		6
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value		493
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss		6
Redeemable Preferred Stock
Available For Sale Securities Continuous Unrealized Loss Position Less Than Twelve Months Fair Value		3,485
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss		278
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value		3,485
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss		278
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, Accumulated Loss		34
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value		2,625
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss		$ 34