Note 1 - Summary of Significant Accounting Policies (Tables)
 12 Months Ended
Dec. 31, 2016
Notes Tables  
Schedule of Related Party Transactions [Table Text Block]
(In thousands)
Years Ended December 31,
  
2016
    
2015
    
2014
  
Legal fees
   $
257
     $
221
     $
212
  
Commissions and fees related to the sale of repossessed commercial real estate and property management
    
-
      
9
      
10
  
Insurance premiums/commissions
    
-
      
1
      
8
  
Other
    
2
      
5
      
9
  
Total
   $
259
     $
236
     $
239
  
Schedule of Earnings Per Share, Basic and Diluted [Table Text Block]
(In thousands, except per share data)
Years Ended December 31,
  
2016
    
2015
    
2014
  
Net income, basic and diluted
   $
16,605
     $
14,992
     $
16,459
  
Less preferred stock dividends and discount accretion
    
-
      
395
      
1,927
  
Net income available to common shareholders, basic and diluted
   $
16,605
     $
14,597
     $
14,532
  
                         
Average common shares outstanding, basic and diluted
    
7,504
      
7,494
      
7,483
  
                         
Net income per common share, basic and diluted
   $
2.21
     $
1.95
     $
1.94
  
Schedule of Share-based Payment Award, Employee Stock Purchase Plan, Valuation Assumptions [Table Text Block]
   
ESPP
  
   
2016
    
2015
    
2014
  
Expected volatility
    
26.3
 %    
32.6
 %    
37.4
 %
Dividend yield
    
.83
      
-
      
-
  
Risk-free interest rate
    
.26
      
.02
      
.04
  
Expected life (in years)
    
.25
      
.25
      
.25
  
                         
Fair value
   $
5.31
     $
5.08
     $
4.69