Note 3 - Investment Securities (Detail) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2010	Dec. 31, 2011
Securities, Continuous Unrealized Loss Position, Fair Value	$ 332,100,000		$ 196,300,000
Securities, Continuous Unrealized Loss Position, Fair Value, Percent of Portfolio	48.00%		27.90%
SecuritiesPledgedAsCollateral	434.8		410.7
Securities Sold under Agreements to Repurchase	58.8		83.6
Available-for-sale Securities, Gross Realized Gains	2,000	467,000
Available-for-sale Securities, Gross Realized Losses		150,000
Income Tax/Benefit Related to Security Gains/Losses, Percentage		39.225%
Liquidation of the Acquired Investment Portfolio from SSB [Member]
Marketable Securities, Realized Gain (Loss)		$ 317,000