Note 9 - Fair Value Measurements (Details) - Assets Measured at Fair Value on a Recurring Basis (USD $) In Thousands, unless otherwise specified	Sep. 30, 2014		Dec. 31, 2013
Note 9 - Fair Value Measurements (Details) - Assets Measured at Fair Value on a Recurring Basis [Line Items]
Investment securities available for sale	$ 1,391,362		$ 1,079,381
US Treasury Securities [Member] | Fair Value, Inputs, Level 1 [Member]
Note 9 - Fair Value Measurements (Details) - Assets Measured at Fair Value on a Recurring Basis [Line Items]
Investment securities available for sale	3,509		3,506
US Treasury Securities [Member]
Note 9 - Fair Value Measurements (Details) - Assets Measured at Fair Value on a Recurring Basis [Line Items]
Investment securities available for sale	3,509		3,506
US Government-sponsored Enterprises Debt Securities [Member] | Fair Value, Inputs, Level 1 [Member]
Note 9 - Fair Value Measurements (Details) - Assets Measured at Fair Value on a Recurring Basis [Line Items]
Investment securities available for sale	441,536		130,492
US Government-sponsored Enterprises Debt Securities [Member]
Note 9 - Fair Value Measurements (Details) - Assets Measured at Fair Value on a Recurring Basis [Line Items]
Investment securities available for sale	441,536		130,492
Residential Mortgage Backed Securities [Member] | Fair Value, Inputs, Level 2 [Member]
Note 9 - Fair Value Measurements (Details) - Assets Measured at Fair Value on a Recurring Basis [Line Items]
Investment securities available for sale	28,353		34,176
Residential Mortgage Backed Securities [Member]
Note 9 - Fair Value Measurements (Details) - Assets Measured at Fair Value on a Recurring Basis [Line Items]
Investment securities available for sale	28,353		34,176
Commercial Mortgage Backed Securities [Member] | Fair Value, Inputs, Level 2 [Member]
Note 9 - Fair Value Measurements (Details) - Assets Measured at Fair Value on a Recurring Basis [Line Items]
Investment securities available for sale	3,021		3,425
Commercial Mortgage Backed Securities [Member]
Note 9 - Fair Value Measurements (Details) - Assets Measured at Fair Value on a Recurring Basis [Line Items]
Investment securities available for sale	3,021		3,425
US States and Political Subdivisions Debt Securities [Member] | Fair Value, Inputs, Level 2 [Member]
Note 9 - Fair Value Measurements (Details) - Assets Measured at Fair Value on a Recurring Basis [Line Items]
Investment securities available for sale	186,620		191,386
US States and Political Subdivisions Debt Securities [Member]
Note 9 - Fair Value Measurements (Details) - Assets Measured at Fair Value on a Recurring Basis [Line Items]
Investment securities available for sale	186,620		191,386
Residential Collateralized Mortgage Obligations [Member] | Fair Value, Inputs, Level 2 [Member]
Note 9 - Fair Value Measurements (Details) - Assets Measured at Fair Value on a Recurring Basis [Line Items]
Investment securities available for sale	229,285		252,896
Residential Collateralized Mortgage Obligations [Member]
Note 9 - Fair Value Measurements (Details) - Assets Measured at Fair Value on a Recurring Basis [Line Items]
Investment securities available for sale	229,285		252,896
Asset-backed Securities [Member] | Fair Value, Inputs, Level 2 [Member]
Note 9 - Fair Value Measurements (Details) - Assets Measured at Fair Value on a Recurring Basis [Line Items]
Investment securities available for sale	8,639		14,555
Asset-backed Securities [Member]
Note 9 - Fair Value Measurements (Details) - Assets Measured at Fair Value on a Recurring Basis [Line Items]
Investment securities available for sale	8,639		14,555
FHLMC And FNMA Stock [Member] | Fair Value, Inputs, Level 1 [Member]
Note 9 - Fair Value Measurements (Details) - Assets Measured at Fair Value on a Recurring Basis [Line Items]
Investment securities available for sale	14,602		13,372
FHLMC And FNMA Stock [Member]
Note 9 - Fair Value Measurements (Details) - Assets Measured at Fair Value on a Recurring Basis [Line Items]
Investment securities available for sale	14,602	[1],[2]	13,372
Domestic Corporate Debt Securities [Member] | Fair Value, Inputs, Level 2 [Member]
Note 9 - Fair Value Measurements (Details) - Assets Measured at Fair Value on a Recurring Basis [Line Items]
Investment securities available for sale	473,138		432,431
Domestic Corporate Debt Securities [Member]
Note 9 - Fair Value Measurements (Details) - Assets Measured at Fair Value on a Recurring Basis [Line Items]
Investment securities available for sale	473,138		432,431
Other Securities [Member] | Fair Value, Inputs, Level 1 [Member]
Note 9 - Fair Value Measurements (Details) - Assets Measured at Fair Value on a Recurring Basis [Line Items]
Investment securities available for sale	795		1,300
Other Securities [Member] | Fair Value, Inputs, Level 2 [Member]
Note 9 - Fair Value Measurements (Details) - Assets Measured at Fair Value on a Recurring Basis [Line Items]
Investment securities available for sale	1,864		1,842
Other Securities [Member]
Note 9 - Fair Value Measurements (Details) - Assets Measured at Fair Value on a Recurring Basis [Line Items]
Investment securities available for sale	2,659		3,142
Fair Value, Inputs, Level 1 [Member]
Note 9 - Fair Value Measurements (Details) - Assets Measured at Fair Value on a Recurring Basis [Line Items]
Investment securities available for sale	460,442		148,670
Fair Value, Inputs, Level 2 [Member]
Note 9 - Fair Value Measurements (Details) - Assets Measured at Fair Value on a Recurring Basis [Line Items]
Investment securities available for sale	$ 930,920		$ 930,711

[1] Federal Home Loan Mortgage Corporation

[2] Federal National Mortgage Association