Note 3 - Loans and Allowance for Loan Losses (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014	Dec. 31, 2014
Receivables [Abstract]
Loans and Leases Receivable, Net of Deferred Income	$ 2,217,388,000		$ 2,217,388,000		$ 2,089,277,000
Loans and Leases Receivable, Period Increase (Decrease)			$ 128,000,000
Loans and Leases Receivable, Percentage, Period Increase (Decrease)			6.10%
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Outstanding Balance	25,900,000		$ 25,900,000
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Carrying Amount, Net	14,100,000		14,100,000
Impaired Financing Receivable, Interest Income, Accrual Method	300,000	$ 600,000	1,000,000	$ 1,300,000
Loans and Leases Receivable, Nonaccrual Loans, Interest Income Recognized	$ 0	$ 0	$ 0	$ 0
Minimum Number of Days Past Due at Period End for Loans Modified as Troubled Debt Restructurings			30 days