Note 3 - Loans and Allowance for Loan Losses (Detail) - Recorded Investment In Loans By Credit Risk Profile (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012	Mar. 31, 2012
Grade	$ 1,127,729	$ 1,103,478	$ 1,050,049
Commercial And Industrial [Member] | Pass [Member]
Grade	380,163	366,571
Commercial And Industrial [Member] | Special Mention [Member]
Grade	3,797	4,393
Commercial And Industrial [Member] | Substandard [Member]
Grade	11,951	12,941
Commercial And Industrial [Member]
Grade	395,911	383,905	344,975
Real Estate Mortgage [Member] | Pass [Member]
Grade	645,678	611,159
Real Estate Mortgage [Member] | Special Mention [Member]
Grade	13,268	14,593
Real Estate Mortgage [Member] | Substandard [Member]
Grade	56,087	76,728
Real Estate Mortgage [Member]
Grade	715,033	702,480	691,071
Real Estate Construction [Member] | Pass [Member]
Grade	5,583	5,163
Real Estate Construction [Member] | Substandard [Member]
Grade	4,529	4,529
Real Estate Construction [Member]
Grade	10,112	9,692	9,208
Consumer And Other [Member] | Pass [Member]
Grade	6,673	7,401
Consumer And Other [Member]
Grade	6,673	7,401	4,795
Pass [Member]
Grade	1,038,097	990,294
Special Mention [Member]
Grade	17,065	18,986
Substandard [Member]
Grade	$ 72,567	$ 94,198