Note 4 - Debt and Equity Securities (Details) (USD $)	3 Months Ended							3 Months Ended			1 Months Ended						3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Dec. 31, 2013	Mar. 31, 2014 Collateralized Mortgage Obligations [Member] Collateralized By Commercial Real Estate [Member]	Dec. 31, 2013 Collateralized Mortgage Obligations [Member] Collateralized By Commercial Real Estate [Member]	Mar. 31, 2014 REMIC And CMO [Member] FHLMC [Member]	Mar. 31, 2014 REMIC And CMO [Member] FNMA [Member]	Mar. 31, 2014 REMIC And CMO [Member] Private Issue CMO [Member]	Mar. 31, 2014 GNMA [Member]	Mar. 31, 2014 FNMA [Member] Private Issue CMO [Member]	Apr. 30, 2014 Subsequent Event [Member]	Mar. 31, 2014 Single Issuer [Member] Trust Preferred Securities [Member]	Mar. 31, 2014 Pooled Issuer [Member] Trust Preferred Securities [Member]	Mar. 31, 2014 Corporate Debt Securities [Member]	Mar. 31, 2014 Municipal [Member]	Mar. 31, 2014 Trust Preferred Securities [Member]	Mar. 31, 2014 Prepay in 2014 [Member]	Mar. 31, 2014 To Prepay In The Second Quarter of 2015 [Member]	Mar. 31, 2014 Pooled Trust Preferred Securities [Member]	Dec. 31, 2013 Collateralized By Commercial Real Estate [Member]
Note 4 - Debt and Equity Securities (Details) [Line Items]
Payments to Acquire Available-for-sale Securities (in Dollars)	$ 48,277,000	$ 171,018,000									$ 1,000,000
Private Issue Collateralized Mortgage Obligations, Number	3																			3
Mortgage Backed Securities Available For Sale, Amortized Cost (in Dollars)				12,800,000	13,900,000
Mortgage-backed Securities Available-for-sale, Fair Value Disclosure (in Dollars)	774,202,000		756,156,000	12,900,000
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions						13	17	6	1	16		1	2	6	24
Texas Ratio, Minimum Review Threshold	50.00%
Fair Value Inputs, Probability of Default	25.00%
Number Of Pooled Trust Securities Assumed To Prepay																	2	2
Significant Assumptions Amount of Prepayments in First QuarterbBy Two Issuers of Pooled Trust Preferred Securities (in Dollars)																		26,700,000
Significant Assumptions Amount of Prepayments in Five Years By Two Issuers of Pooled Trust Preferred Securities (in Dollars)																		21,500,000
Number Of Instruments Below Investment Grade																4
Number Of Instruments Carried Under Fair Value Option Below Investment Grade																1
Number Of Instruments Below Investment Grade Evalatued For Default																3
Other than Temporary Impairment Losses, Investments, Available-for-sale Securities (in Dollars)								$ 0	$ 0
Number Of Instruments With OTTI Charges Recorded																			2