Note 6: Investment Securities: Schedule of Gross Unrealized Losses and Estimated Fair Value of Investments (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
TotalUnrealizedLossesAndEstimatedFairValueMember
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	$ 244,142	$ 106,136
AvailableForSaleSecuritiesContinuousUnrealizedLossPositionLessThan12MonthsAggregateLosses3	(6,139)	(814)
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	1	414
AvailableforsaleSecuritiesContinuousUnrealizedLossPosition12MonthsOrLongerAggregateLosses3		(8)
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	244,143	106,550
AvailableForSaleSecuritiesContinuousUnrealizedLossPositionAggregateLosses3	(6,139)	(822)
Collateralized Mortgage Obligations
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value		414
AvailableforsaleSecuritiesContinuousUnrealizedLossPosition12MonthsOrLongerAggregateLosses3		(8)
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value		414
AvailableForSaleSecuritiesContinuousUnrealizedLossPositionAggregateLosses3		(8)
US Government Agencies Debt Securities
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	20,000
AvailableForSaleSecuritiesContinuousUnrealizedLossPositionLessThan12MonthsAggregateLosses3	(2,170)
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	20,000
AvailableForSaleSecuritiesContinuousUnrealizedLossPositionAggregateLosses3	(2,170)
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	182,088	106,136
AvailableForSaleSecuritiesContinuousUnrealizedLossPositionLessThan12MonthsAggregateLosses3	(2,862)	(814)
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	1
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	182,089	106,136
AvailableForSaleSecuritiesContinuousUnrealizedLossPositionAggregateLosses3	(2,862)	(814)
US States and Political Subdivisions Debt Securities
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	42,054
AvailableForSaleSecuritiesContinuousUnrealizedLossPositionLessThan12MonthsAggregateLosses3	(1,107)
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	42,054
AvailableForSaleSecuritiesContinuousUnrealizedLossPositionAggregateLosses3	$ (1,107)