Note 4 - Allowance for Loan Losses (Detail) - Change in Allowance for Loan Losses by Major Classification (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012	Dec. 31, 2012	Dec. 31, 2011
Balance at	$ 33,921	$ 34,757	$ 35,907	$ 33,677
Provision charged to operations	3,180	2,725
Loans charged off	(6,221)	(2,533)
Recoveries of loans previously charged off	1,055	888
Real Estate - Residential Mortgage (Member)
Balance at	2,296	2,653	2,358	2,379
Provision charged to operations	332	386
Loans charged off	(473)	(122)
Recoveries of loans previously charged off	79	10
Real Estate Construction [Member]
Balance at	345	467	424	480
Provision charged to operations	(79)	(13)
commercial, financial and agricultural (Member)
Balance at	7,765	10,410	9,824	10,040
Provision charged to operations	67	335
Loans charged off	(2,134)
Recoveries of loans previously charged off	8	35
Equity Lines (Member)
Balance at	863	917	885	912
Provision charged to operations	(12)	126
Loans charged off	(37)	(121)
Recoveries of loans previously charged off	27
consumer (Member)
Balance at	268	269	283	319
Provision charged to operations	122	(9)
Loans charged off	(184)	(90)
Recoveries of loans previously charged off	47	49
consumer finance (Member)
Balance at	22,384	20,041	22,133	19,547
Provision charged to operations	2,750	1,900
Loans charged off	(3,393)	(2,200)
Recoveries of loans previously charged off	$ 894	$ 794