Note 1 - Significant Accounting Policies (Details Textual) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2016 USD ($) shares	Jun. 30, 2015 shares	Jun. 30, 2016 USD ($) shares	Jun. 30, 2015 shares	Dec. 31, 2015 USD ($)
Restricted Stock [Member]
Incremental Common Shares Attributable to Participating Nonvested Shares with Non-forfeitable Dividend Rights	150,000	100,000	150,000	100,000
Employee Stock Option [Member]
Incremental Common Shares Attributable to Dilutive Effect of Share-based Payment Arrangements	92,000	108,000	92,000	108,000
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	7,000	91,000	7,000	91,000
Mortgage Loans [Member]
Servicing Asset | $	$ 597.0		$ 597.0
Core Deposits [Member]
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life			10 years
Number of Unconsolidated Business Trusts Formed to Issue Trust Preferred Securities	5		5
Interest Income on Commercial and Mortgage Loans Discontinued Period			90 days
Maximum Delinquency Period for Consumer and Credit Card Loans to be Charged Off			120 days
Loans Receivable Held-for-sale, Net, Not Part of Disposal Group, Mortgage | $	$ 2.9		$ 2.9		$ 1.3