Note 10 - Income Taxes (Tables)
 12 Months Ended
Dec. 31, 2016
Notes Tables  
Schedule of Components of Income Tax Expense (Benefit) [Table Text Block]
December 31, (In thousands)
  
2016
    
2015
    
2014
  
Currently payable
   $
5,556
     $
3,662
     $
2,168
  
Deferred
   
885
      
1,631
      
3,931
  
Income tax expense
   $
6,441
     $
5,293
     $
6,099
  
Schedule of Components of Income Tax Expense (Benefit) Recorded to Shareholders' Equity [Table Text Block]
December 31, (In thousands)
  
2016
    
2015
    
2014
  
Unfunded status of postretirement benefits
   $
211
     $
(74
 )   $
(382
 )
Net unrealized securities (losses) gains
    
(3,545
 )    
(1,052
 )    
4,737
  
Total income tax (benefit) expense recorded directly to shareholders’ equity
   $
(3,334
 )   $
(1,126
 )   $
4,355
  
Schedule of Effective Income Tax Rate Reconciliation [Table Text Block]
December 31,
  
2016
    
2015
    
2014
  
Federal statutory rate
    
35.0
 %    
35.0
 %    
35.0
 %
Changes from statutory rates resulting from:
                        
Tax-exempt interest
    
(4.6
 )    
(5.8
 )    
(5.2
 )
Nondeductible interest to carry tax-exempt obligations
    
.2
      
.2
      
.2
  
Premium income not subject to tax
    
(1.3
 )    
(1.5
 )    
(1.2
 )
Company-owned life insurance
    
(1.5
 )    
(1.6
 )    
(1.9
 )
Uncertain tax position
    
-
      
-
      
(.3
 )
Other, net
    
.1
      
(.2
 )    
.4
  
Effective tax rate on pretax income
   
27.9
 %    
26.1
 %    
27.0
 %
Schedule of Deferred Tax Assets and Liabilities [Table Text Block]
December 31, (In thousands)
  
2016
    
2015
  
Assets
 
 
 
 
 
 
 
 
Allowance for loan losses
   $
3,285
     $
3,625
  
Deferred directors’ fees
    
236
      
242
  
Postretirement benefit obligations
    
5,825
      
5,665
  
Other real estate owned
    
1,303
      
1,968
  
Self-funded insurance
    
232
      
230
  
Paid time off
    
815
      
756
  
Depreciation
    
1,630
      
1,440
  
Intangibles
    
1,878
      
2,432
  
Unrealized loss on available for sale investment securities, net
    
1,811
      
-
  
Other
    
239
      
307
  
Total deferred tax assets
    
17,254
      
16,665
  
Liabilities
 
 
 
 
 
 
 
 
Unrealized gains on available for sale investment securities, net
    
-
      
1,734
  
Prepaid expenses
    
153
      
306
  
Federal Home Loan Bank stock dividends
    
1,035
      
1,035
  
Deferred loan fees
    
846
      
806
  
Other
    
52
      
65
  
Total deferred tax liabilities
    
2,086
      
3,946
  
Net deferred tax asset
   $
15,168
     $
12,719