Note 4 - Loans and Allowance for Loan Losses (Detail) - Loans by credit risk rating, segregated by class of loans: (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Loans, excluding acquired loans	$ 1,628,513	$ 1,579,769
Loans acquired, covered by FDIC loss share	210,842	158,075
Loans acquired, not covered by FDIC loss share	82,764
Total loans	1,922,119	1,737,844
Consumer Loans [Member] | Risk Rate 1-4 [Member] | Credit Cards [Member]
Loans, excluding acquired loans	184,989	189,365
Consumer Loans [Member] | Risk Rate 1-4 [Member] | Student Loans [Member]
Loans, excluding acquired loans	31,911	44,936
Consumer Loans [Member] | Risk Rate 1-4 [Member] | Other Consumer [Member]
Loans, excluding acquired loans	103,597	107,217
Consumer Loans [Member] | Risk Rate 1-4 [Member] | Total Consumer [Member]
Loans, excluding acquired loans	320,497	341,518
Consumer Loans [Member] | Risk Rate 5 [Member] | Other Consumer [Member]
Loans, excluding acquired loans	7	12
Consumer Loans [Member] | Risk Rate 5 [Member] | Total Consumer [Member]
Loans, excluding acquired loans	7	12
Consumer Loans [Member] | Risk Rate 6 [Member] | Credit Cards [Member]
Loans, excluding acquired loans	547	605
Consumer Loans [Member] | Risk Rate 6 [Member] | Student Loans [Member]
Loans, excluding acquired loans	2,234	2,483
Consumer Loans [Member] | Risk Rate 6 [Member] | Other Consumer [Member]
Loans, excluding acquired loans	1,660	1,906
Consumer Loans [Member] | Risk Rate 6 [Member] | Total Consumer [Member]
Loans, excluding acquired loans	4,441	4,994
Consumer Loans [Member] | Risk Rate 7 [Member] | Other Consumer [Member]
Loans, excluding acquired loans	33	50
Consumer Loans [Member] | Risk Rate 7 [Member] | Total Consumer [Member]
Loans, excluding acquired loans	33	50
Consumer Loans [Member] | Risk Rate 8 [Member] | Other Consumer [Member]
Loans, excluding acquired loans	22	26
Consumer Loans [Member] | Risk Rate 8 [Member] | Total Consumer [Member]
Loans, excluding acquired loans	22	26
Consumer Loans [Member] | Credit Cards [Member]
Loans, excluding acquired loans	185,536	189,970
Consumer Loans [Member] | Student Loans [Member]
Loans, excluding acquired loans	34,145	47,419
Consumer Loans [Member] | Other Consumer [Member]
Loans, excluding acquired loans	105,319	109,211
Consumer Loans [Member] | Total Consumer [Member]
Loans, excluding acquired loans	325,000	346,600
Real Estate Loans [Member] | Risk Rate 1-4 [Member] | Construction Loans [Member]
Loans, excluding acquired loans	131,873	100,534
Real Estate Loans [Member] | Risk Rate 1-4 [Member] | Single Family Residential Loans [Member]
Loans, excluding acquired loans	348,628	345,880
Real Estate Loans [Member] | Risk Rate 1-4 [Member] | Other Commercial Real Estate Loans [Member]
Loans, excluding acquired loans	540,986	491,466
Real Estate Loans [Member] | Risk Rate 1-4 [Member] | Total Real Estate [Member]
Loans, excluding acquired loans	1,021,487	937,880
Real Estate Loans [Member] | Risk Rate 5 [Member] | Construction Loans [Member]
Loans, excluding acquired loans	30	3,699
Real Estate Loans [Member] | Risk Rate 5 [Member] | Single Family Residential Loans [Member]
Loans, excluding acquired loans	1,458	1,377
Real Estate Loans [Member] | Risk Rate 5 [Member] | Other Commercial Real Estate Loans [Member]
Loans, excluding acquired loans	8,484	8,465
Real Estate Loans [Member] | Risk Rate 5 [Member] | Total Real Estate [Member]
Loans, excluding acquired loans	9,972	13,541
Real Estate Loans [Member] | Risk Rate 6 [Member] | Construction Loans [Member]
Loans, excluding acquired loans	6,229	5,592
Real Estate Loans [Member] | Risk Rate 6 [Member] | Single Family Residential Loans [Member]
Loans, excluding acquired loans	6,821	7,821
Real Estate Loans [Member] | Risk Rate 6 [Member] | Other Commercial Real Estate Loans [Member]
Loans, excluding acquired loans	18,696	36,441
Real Estate Loans [Member] | Risk Rate 6 [Member] | Total Real Estate [Member]
Loans, excluding acquired loans	31,746	49,854
Real Estate Loans [Member] | Risk Rate 7 [Member] | Single Family Residential Loans [Member]
Loans, excluding acquired loans		16
Real Estate Loans [Member] | Risk Rate 7 [Member] | Total Real Estate [Member]
Loans, excluding acquired loans		16
Real Estate Loans [Member] | Construction Loans [Member]
Loans, excluding acquired loans	138,132	109,825
Real Estate Loans [Member] | Single Family Residential Loans [Member]
Loans, excluding acquired loans	356,907	355,094
Real Estate Loans [Member] | Other Commercial Real Estate Loans [Member]
Loans, excluding acquired loans	568,166	536,372
Real Estate Loans [Member] | Total Real Estate [Member]
Loans, excluding acquired loans	1,063,205	1,001,291
Commercial Loans [Member] | Risk Rate 1-4 [Member] | Commercial [Member]
Loans, excluding acquired loans	138,948	136,107
Commercial Loans [Member] | Risk Rate 1-4 [Member] | Agricultural Loans [Member]
Loans, excluding acquired loans	93,357	84,747
Commercial Loans [Member] | Risk Rate 1-4 [Member] | Total Commercial [Member]
Loans, excluding acquired loans	232,305	220,854
Commercial Loans [Member] | Risk Rate 5 [Member] | Commercial [Member]
Loans, excluding acquired loans	114	510
Commercial Loans [Member] | Risk Rate 5 [Member] | Agricultural Loans [Member]
Loans, excluding acquired loans		148
Commercial Loans [Member] | Risk Rate 5 [Member] | Total Commercial [Member]
Loans, excluding acquired loans	114	658
Commercial Loans [Member] | Risk Rate 6 [Member] | Commercial [Member]
Loans, excluding acquired loans	2,235	4,762
Commercial Loans [Member] | Risk Rate 6 [Member] | Agricultural Loans [Member]
Loans, excluding acquired loans	448	833
Commercial Loans [Member] | Risk Rate 6 [Member] | Total Commercial [Member]
Loans, excluding acquired loans	2,683	5,595
Commercial Loans [Member] | Risk Rate 7 [Member] | Commercial [Member]
Loans, excluding acquired loans	39	43
Commercial Loans [Member] | Risk Rate 7 [Member] | Total Commercial [Member]
Loans, excluding acquired loans	39	43
Commercial Loans [Member] | Commercial [Member]
Loans, excluding acquired loans	141,336	141,422
Commercial Loans [Member] | Agricultural Loans [Member]
Loans, excluding acquired loans	93,805	85,728
Commercial Loans [Member] | Total Commercial [Member]
Loans, excluding acquired loans	235,141	227,150
Risk Rate 1-4 [Member] | Other Loans [Member]
Loans, excluding acquired loans	5,167	4,728
Risk Rate 1-4 [Member]
Loans acquired, covered by FDIC loss share	210,842	158,075
Loans acquired, not covered by FDIC loss share	82,764
Total loans	1,873,062	1,663,055
Risk Rate 5 [Member]
Total loans	10,093	14,211
Risk Rate 6 [Member]
Total loans	38,870	60,443
Risk Rate 7 [Member]
Total loans	72	109
Risk Rate 8 [Member]
Total loans	22	26
Other Loans [Member]
Loans, excluding acquired loans	$ 5,167	$ 4,728