Note 6. Fair Value Disclosures: Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012	Dec. 31, 2012	Dec. 31, 2011
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Value	$ 12,860	$ 16,526	$ 17,181	$ 22,665
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Gain Loss Included In Earnings1	1,490	(1,212)
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Gain Loss Included In Other Comprehensive Income Loss	(1,309)	1,162
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Sales	(4,034)	(7,087)
Fair Value Measurement With UnobservableInputs Reconciliation Recurring Basis Asset Repayments And Amortization	(468)	(1,054)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases		2,135
OtherThanTemporaryImpairmentLossesInvestmentsPortionRecognizedInEarningsUnobservableInputsReconciliation		(83)
Residential Mortgage Backed Securities Member
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Value	9,755	13,350	14,053	22,127
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Gain Loss Included In Earnings1	1,490	(1,212)
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Gain Loss Included In Other Comprehensive Income Loss	(1,292)	671
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Sales	(4,034)	(7,087)
Fair Value Measurement With UnobservableInputs Reconciliation Recurring Basis Asset Repayments And Amortization	(462)	(1,066)
OtherThanTemporaryImpairmentLossesInvestmentsPortionRecognizedInEarningsUnobservableInputsReconciliation		(83)
Commercial Mortgage Backed Securities
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Value	576	533	570	538
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Gain Loss Included In Other Comprehensive Income Loss	6	(5)
US States and Political Subdivisions Debt Securities
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Value	2,529	2,643	2,558
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Gain Loss Included In Other Comprehensive Income Loss	(23)	496
Fair Value Measurement With UnobservableInputs Reconciliation Recurring Basis Asset Repayments And Amortization	(6)	12
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases		$ 2,135