Note 4 - Loans and Allowance for Loan Losses (Details) - Loans by credit risk rating, segregated by class of loans: (USD $) In Thousands, unless otherwise specified	Jun. 30, 2013	Dec. 31, 2012
Financing Receivable, Recorded Investment [Line Items]
Financing receivables	$ 1,877,631	$ 1,922,119
Loans acquired, covered by FDIC loss share	163,736	210,842
Loans acquired, not covered by FDIC loss share	63,500	82,764
Consumer Loans [Member] | Credit Cards [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing receivables	173,536	185,536
Consumer Loans [Member] | Student Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing receivables	30,106	34,145
Consumer Loans [Member] | Other Consumer [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing receivables	103,765	105,319
Consumer Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing receivables	307,407	325,000
Consumer Loans [Member] | Risk Rate 1-4 [Member] | Credit Cards [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing receivables	173,029	184,989
Consumer Loans [Member] | Risk Rate 1-4 [Member] | Student Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing receivables	27,852	31,911
Consumer Loans [Member] | Risk Rate 1-4 [Member] | Other Consumer [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing receivables	102,272	103,597
Consumer Loans [Member] | Risk Rate 1-4 [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing receivables	303,153	320,497
Consumer Loans [Member] | Risk Rate 5 [Member] | Other Consumer [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing receivables	4	7
Consumer Loans [Member] | Risk Rate 5 [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing receivables	4	7
Consumer Loans [Member] | Risk Rate 6 [Member] | Credit Cards [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing receivables	507	547
Consumer Loans [Member] | Risk Rate 6 [Member] | Student Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing receivables	2,254	2,234
Consumer Loans [Member] | Risk Rate 6 [Member] | Other Consumer [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing receivables	1,408	1,660
Consumer Loans [Member] | Risk Rate 6 [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing receivables	4,169	4,441
Consumer Loans [Member] | Risk Rate 7 [Member] | Other Consumer [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing receivables	62	33
Consumer Loans [Member] | Risk Rate 7 [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing receivables	62	33
Consumer Loans [Member] | Risk Rate 8 [Member] | Other Consumer [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing receivables	19	22
Consumer Loans [Member] | Risk Rate 8 [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing receivables	19	22
Real Estate Loans [Member] | Construction Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing receivables	142,902	138,132
Real Estate Loans [Member] | Single Family Residential Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing receivables	364,239	356,907
Real Estate Loans [Member] | Other Commercial Real Estate Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing receivables	572,110	568,166
Real Estate Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing receivables	1,079,251	1,063,205
Real Estate Loans [Member] | Risk Rate 1-4 [Member] | Construction Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing receivables	138,888	131,873
Real Estate Loans [Member] | Risk Rate 1-4 [Member] | Single Family Residential Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing receivables	356,634	348,628
Real Estate Loans [Member] | Risk Rate 1-4 [Member] | Other Commercial Real Estate Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing receivables	542,950	540,986
Real Estate Loans [Member] | Risk Rate 1-4 [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing receivables	1,038,472	1,021,487
Real Estate Loans [Member] | Risk Rate 5 [Member] | Construction Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing receivables	77	30
Real Estate Loans [Member] | Risk Rate 5 [Member] | Single Family Residential Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing receivables	1,440	1,458
Real Estate Loans [Member] | Risk Rate 5 [Member] | Other Commercial Real Estate Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing receivables	7,264	8,484
Real Estate Loans [Member] | Risk Rate 5 [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing receivables	8,781	9,972
Real Estate Loans [Member] | Risk Rate 6 [Member] | Construction Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing receivables	3,937	6,229
Real Estate Loans [Member] | Risk Rate 6 [Member] | Single Family Residential Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing receivables	6,165	6,821
Real Estate Loans [Member] | Risk Rate 6 [Member] | Other Commercial Real Estate Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing receivables	21,896	18,696
Real Estate Loans [Member] | Risk Rate 6 [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing receivables	31,998	31,746
Commercial Loans [Member] | Commercial [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing receivables	152,122	141,336
Commercial Loans [Member] | Agricultural Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing receivables	107,113	93,805
Commercial Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing receivables	259,235	235,141
Commercial Loans [Member] | Risk Rate 1-4 [Member] | Commercial [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing receivables	149,631	138,948
Commercial Loans [Member] | Risk Rate 1-4 [Member] | Agricultural Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing receivables	106,936	93,357
Commercial Loans [Member] | Risk Rate 1-4 [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing receivables	256,567	232,305
Commercial Loans [Member] | Risk Rate 5 [Member] | Commercial [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing receivables	203	114
Commercial Loans [Member] | Risk Rate 5 [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing receivables	203	114
Commercial Loans [Member] | Risk Rate 6 [Member] | Commercial [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing receivables	2,288	2,235
Commercial Loans [Member] | Risk Rate 6 [Member] | Agricultural Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing receivables	177	448
Commercial Loans [Member] | Risk Rate 6 [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing receivables	2,465	2,683
Commercial Loans [Member] | Risk Rate 7 [Member] | Commercial [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing receivables		39
Commercial Loans [Member] | Risk Rate 7 [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing receivables		39
Other Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing receivables	4,502	5,167
Risk Rate 1-4 [Member] | Other Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing receivables	4,502	5,167
Risk Rate 1-4 [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing receivables	1,829,930	1,873,062
Loans acquired, covered by FDIC loss share	163,736	210,842
Loans acquired, not covered by FDIC loss share	63,500	82,764
Risk Rate 5 [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing receivables	8,988	10,093
Risk Rate 6 [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing receivables	38,632	38,870
Risk Rate 7 [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing receivables	62	72
Risk Rate 8 [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing receivables	$ 19	$ 22