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	Sep. 30, 2014	Dec. 31, 2013
Financing Receivable, Recorded Investment [Line Items]
Financing receivables	$ 2,757,592	$ 2,404,935
Loans acquired, not covered by FDIC loss share	676,056	515,644
Loans acquired, covered by FDIC loss share	118,158	146,653
Credit Cards [Member] | Consumer Loans [Member] | Risk Rate 1-4 [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing receivables	175,305	184,415
Credit Cards [Member] | Consumer Loans [Member] | Risk Rate 6 [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing receivables	517	520
Credit Cards [Member] | Consumer Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing receivables	175,822	184,935
Student Loans [Member] | Consumer Loans [Member] | Risk Rate 1-4 [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing receivables		23,642
Student Loans [Member] | Consumer Loans [Member] | Risk Rate 6 [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing receivables		2,264
Student Loans [Member] | Consumer Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing receivables		25,906
Other Consumer [Member] | Consumer Loans [Member] | Risk Rate 1-4 [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing receivables	104,408	97,655
Other Consumer [Member] | Consumer Loans [Member] | Risk Rate 5 [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing receivables		2
Other Consumer [Member] | Consumer Loans [Member] | Risk Rate 6 [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing receivables	1,055	1,121
Other Consumer [Member] | Consumer Loans [Member] | Risk Rate 7 [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing receivables	45	56
Other Consumer [Member] | Consumer Loans [Member] | Risk Rate 8 [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing receivables		17
Other Consumer [Member] | Consumer Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing receivables	105,508	98,851
Construction Loans [Member] | Real Estate Loans [Member] | Risk Rate 1-4 [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing receivables	157,714	142,213
Construction Loans [Member] | Real Estate Loans [Member] | Risk Rate 5 [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing receivables	41	71
Construction Loans [Member] | Real Estate Loans [Member] | Risk Rate 6 [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing receivables	5,609	4,174
Construction Loans [Member] | Real Estate Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing receivables	163,364	146,458
Single Family Residential Loans [Member] | Real Estate Loans [Member] | Risk Rate 1-4 [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing receivables	426,747	383,934
Single Family Residential Loans [Member] | Real Estate Loans [Member] | Risk Rate 5 [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing receivables	1,891	1,412
Single Family Residential Loans [Member] | Real Estate Loans [Member] | Risk Rate 6 [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing receivables	8,204	6,939
Single Family Residential Loans [Member] | Real Estate Loans [Member] | Risk Rate 7 [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing receivables	83
Single Family Residential Loans [Member] | Real Estate Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing receivables	436,925	392,285
Other Commercial Real Estate Loans [Member] | Real Estate Loans [Member] | Risk Rate 1-4 [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing receivables	668,403	600,045
Other Commercial Real Estate Loans [Member] | Real Estate Loans [Member] | Risk Rate 5 [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing receivables	2,845	7,597
Other Commercial Real Estate Loans [Member] | Real Estate Loans [Member] | Risk Rate 6 [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing receivables	10,600	18,691
Other Commercial Real Estate Loans [Member] | Real Estate Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing receivables	681,848	626,333
Commercial [Member] | Commercial Loans [Member] | Risk Rate 1-4 [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing receivables	239,308	162,118
Commercial [Member] | Commercial Loans [Member] | Risk Rate 5 [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing receivables	2,550	200
Commercial [Member] | Commercial Loans [Member] | Risk Rate 6 [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing receivables	7,318	2,001
Commercial [Member] | Commercial Loans [Member] | Risk Rate 7 [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing receivables	10	10
Commercial [Member] | Commercial Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing receivables	249,186	164,329
Agricultural Loans [Member] | Commercial Loans [Member] | Risk Rate 1-4 [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing receivables	143,853	98,761
Agricultural Loans [Member] | Commercial Loans [Member] | Risk Rate 6 [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing receivables	1,304	125
Agricultural Loans [Member] | Commercial Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing receivables	145,157	98,886
Other Loans [Member] | Risk Rate 1-4 [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing receivables	5,568	4,655
Other Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing receivables	5,568	4,655
Consumer Loans [Member] | Risk Rate 1-4 [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing receivables	279,713	305,712
Consumer Loans [Member] | Risk Rate 5 [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing receivables		2
Consumer Loans [Member] | Risk Rate 6 [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing receivables	1,572	3,905
Consumer Loans [Member] | Risk Rate 7 [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing receivables	45	56
Consumer Loans [Member] | Risk Rate 8 [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing receivables		17
Consumer Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing receivables	281,330	309,692
Real Estate Loans [Member] | Risk Rate 1-4 [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing receivables	1,252,864	1,126,192
Real Estate Loans [Member] | Risk Rate 5 [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing receivables	4,777	9,080
Real Estate Loans [Member] | Risk Rate 6 [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing receivables	24,413	29,804
Real Estate Loans [Member] | Risk Rate 7 [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing receivables	83
Real Estate Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing receivables	1,282,137	1,165,076
Commercial Loans [Member] | Risk Rate 1-4 [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing receivables	383,161	260,879
Commercial Loans [Member] | Risk Rate 5 [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing receivables	2,550	200
Commercial Loans [Member] | Risk Rate 6 [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing receivables	8,622	2,126
Commercial Loans [Member] | Risk Rate 7 [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing receivables	10	10
Commercial Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing receivables	394,343	263,215
Risk Rate 1-4 [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing receivables	2,650,204	2,301,188
Loans acquired, not covered by FDIC loss share	610,740	457,097
Loans acquired, covered by FDIC loss share	118,158	146,653
Risk Rate 5 [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing receivables	15,970	9,282
Loans acquired, not covered by FDIC loss share	8,643
Risk Rate 6 [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing receivables	89,401	94,382
Loans acquired, not covered by FDIC loss share	54,794	58,547
Risk Rate 7 [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing receivables	2,011	66
Loans acquired, not covered by FDIC loss share	1,873
Risk Rate 8 [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing receivables	6	17
Loans acquired, not covered by FDIC loss share	$ 6