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, 2013	Dec. 31, 2012
Financing Receivable, Recorded Investment [Line Items]
Financing receivables	$ 1,958,178	$ 1,922,119
Loans acquired, covered by FDIC loss share	148,884	210,842
Loans acquired, not covered by FDIC loss share	68,133	82,764
Consumer Loans [Member] | Credit Cards [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing receivables	177,463	185,536
Consumer Loans [Member] | Student Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing receivables	28,392	34,145
Consumer Loans [Member] | Other Consumer [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing receivables	101,399	105,319
Consumer Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing receivables	307,254	325,000
Consumer Loans [Member] | Risk Rate 1-4 [Member] | Credit Cards [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing receivables	176,943	184,989
Consumer Loans [Member] | Risk Rate 1-4 [Member] | Student Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing receivables	25,426	31,911
Consumer Loans [Member] | Risk Rate 1-4 [Member] | Other Consumer [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing receivables	100,089	103,597
Consumer Loans [Member] | Risk Rate 1-4 [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing receivables	302,458	320,497
Consumer Loans [Member] | Risk Rate 5 [Member] | Other Consumer [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing receivables	3	7
Consumer Loans [Member] | Risk Rate 5 [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing receivables	3	7
Consumer Loans [Member] | Risk Rate 6 [Member] | Credit Cards [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing receivables	520	547
Consumer Loans [Member] | Risk Rate 6 [Member] | Student Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing receivables	2,966	2,234
Consumer Loans [Member] | Risk Rate 6 [Member] | Other Consumer [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing receivables	1,229	1,660
Consumer Loans [Member] | Risk Rate 6 [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing receivables	4,715	4,441
Consumer Loans [Member] | Risk Rate 7 [Member] | Other Consumer [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing receivables	60	33
Consumer Loans [Member] | Risk Rate 7 [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing receivables	60	33
Consumer Loans [Member] | Risk Rate 8 [Member] | Other Consumer [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing receivables	18	22
Consumer Loans [Member] | Risk Rate 8 [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing receivables	18	22
Real Estate Loans [Member] | Construction Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing receivables	161,024	138,132
Real Estate Loans [Member] | Single Family Residential Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing receivables	375,703	356,907
Real Estate Loans [Member] | Other Commercial Real Estate Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing receivables	602,463	568,166
Real Estate Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing receivables	1,139,190	1,063,205
Real Estate Loans [Member] | Risk Rate 1-4 [Member] | Construction Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing receivables	156,701	131,873
Real Estate Loans [Member] | Risk Rate 1-4 [Member] | Single Family Residential Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing receivables	368,159	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	573,657	540,986
Real Estate Loans [Member] | Risk Rate 1-4 [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing receivables	1,098,517	1,021,487
Real Estate Loans [Member] | Risk Rate 5 [Member] | Construction Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing receivables	74	30
Real Estate Loans [Member] | Risk Rate 5 [Member] | Single Family Residential Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing receivables	1,423	1,458
Real Estate Loans [Member] | Risk Rate 5 [Member] | Other Commercial Real Estate Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing receivables	8,156	8,484
Real Estate Loans [Member] | Risk Rate 5 [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing receivables	9,653	9,972
Real Estate Loans [Member] | Risk Rate 6 [Member] | Construction Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing receivables	4,249	6,229
Real Estate Loans [Member] | Risk Rate 6 [Member] | Single Family Residential Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing receivables	6,121	6,821
Real Estate Loans [Member] | Risk Rate 6 [Member] | Other Commercial Real Estate Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing receivables	20,650	18,696
Real Estate Loans [Member] | Risk Rate 6 [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing receivables	31,020	31,746
Commercial Loans [Member] | Commercial [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing receivables	154,508	141,336
Commercial Loans [Member] | Agricultural Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing receivables	135,633	93,805
Commercial Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing receivables	290,141	235,141
Commercial Loans [Member] | Risk Rate 1-4 [Member] | Commercial [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing receivables	152,158	138,948
Commercial Loans [Member] | Risk Rate 1-4 [Member] | Agricultural Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing receivables	135,471	93,357
Commercial Loans [Member] | Risk Rate 1-4 [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing receivables	287,629	232,305
Commercial Loans [Member] | Risk Rate 5 [Member] | Commercial [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing receivables	186	114
Commercial Loans [Member] | Risk Rate 5 [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing receivables	186	114
Commercial Loans [Member] | Risk Rate 6 [Member] | Commercial [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing receivables	2,164	2,235
Commercial Loans [Member] | Risk Rate 6 [Member] | Agricultural Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing receivables	162	448
Commercial Loans [Member] | Risk Rate 6 [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing receivables	2,326	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	4,576	5,167
Risk Rate 1-4 [Member] | Other Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing receivables	4,576	5,167
Risk Rate 1-4 [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing receivables	1,910,197	1,873,062
Loans acquired, covered by FDIC loss share	148,884	210,842
Loans acquired, not covered by FDIC loss share	68,133	82,764
Risk Rate 5 [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing receivables	9,842	10,093
Risk Rate 6 [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing receivables	38,061	38,870
Risk Rate 7 [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing receivables	60	72
Risk Rate 8 [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing receivables	$ 18	$ 22