Note 3 - Investment Securities (Tables)
 12 Months Ended
Dec. 31, 2016
Notes Tables  
Schedule of AFS and HTM Reconciliation [Table Text Block]
December 31, 2016 (In thousands)
  
Amortized
Cost
    
Gross
Unrealized
Gains
    
Gross
Unrealized
Losses
    
Estimated
Fair Value
  
Available For Sale
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Obligations of U.S. government-sponsored entities
   $
71,941
     $
213
     $
460
     $
71,694
  
Obligations of states and political subdivisions
    
134,055
      
773
      
2,536
      
132,292
  
Mortgage-backed securities – residential
    
225,489
      
1,505
      
2,687
      
224,307
  
Mortgage-backed securities – commercial
   
47,164
      
6
      
1,557
      
45,613
  
Corporate debt securities
    
6,565
      
1
      
441
      
6,125
  
Mutual funds and equity securities
    
824
      
20
      
11
      
833
  
Total securities – available for sale
   $
486,038
     $
2,518
     $
7,692
     $
480,864
  
Held To Maturity
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Obligations of states and political subdivisions
   $
3,488
     $
109
     $
-
     $
3,597
  
December 31, 2015 (In thousands)
  
Amortized
Cost
    
Gross
Unrealized
Gains
    
Gross
Unrealized
Losses
    
Estimated
Fair Value
  
Available For Sale
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Obligations of U.S. government-sponsored entities
   $
107,135
     $
309
     $
538
     $
106,906
  
Obligations of states and political subdivisions
    
147,875
      
2,604
      
213
      
150,266
  
Mortgage-backed securities – residential
    
294,140
      
5,210
      
1,489
      
297,861
  
Mortgage-backed securities – commercial
   
20,655
      
52
      
123
      
20,584
  
Corporate debt securities
    
6,629
      
11
      
800
      
5,840
  
Mutual funds and equity securities
    
814
      
-
      
69
      
745
  
Total securities – available for sale
   $
577,248
     $
8,186
     $
3,232
     $
582,202
  
Held To Maturity
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Obligations of states and political subdivisions
   $
3,611
     $
198
     $
-
     $
3,809
  
Investments Classified by Contractual Maturity Date [Table Text Block]
   
Available For Sale
    
Held To Maturity
  
December 31, 2016 (In thousands)
  
Amortized
Cost
    
Estimated
Fair Value
    
Amortized
Cost
    
Estimated
Fair Value
  
Due in one year or less
   $
19,743
     $
19,762
     $
-
     $
-
  
Due after one year through five years
    
87,628
      
87,504
      
-
      
-
  
Due after five years through ten years
    
85,007
      
83,317
      
570
      
630
  
Due after ten years
    
20,183
      
19,528
      
2,918
      
2,967
  
Mortgage-backed securities
   
272,653
      
269,920
      
-
      
-
  
Total
   $
485,214
     $
480,031
     $
3,488
     $
3,597
  
Realized Gain (Loss) on Investments [Table Text Block]
(In thousands)
  
2016
    
2015
    
2014
  
                         
Gross realized gains
   $
4,191
     $
224
     $
190
  
Gross realized losses
    
193
      
53
      
253
  
Net realized gain (loss)
   $
3,998
     $
171
     $
(63
 )
                         
Income tax provision (benefit) related to net realized gain (loss)
   $
1,399
     $
60
     $
(22
 )
Schedule of Unrealized Loss on Investments [Table Text Block]
   
Less than 12 Months
    
12 Months or More
    
Total
  
December 31, 2016 (In thousands)
  
Fair
Value
    
Unrealized
Losses
    
Fair
Value
    
Unrealized
Losses
    
Fair
Value
    
Unrealized
Losses
  
Obligations of U.S. government-sponsored entities
   $
51,657
     $
460
     $
-
     $
-
     $
51,657
     $
460
  
Obligations of states and political subdivisions
    
91,728
      
2,526
      
1,999
      
10
      
93,727
      
2,536
  
Mortgage-backed securities – residential
    
154,397
      
2,485
      
5,841
      
202
      
160,238
      
2,687
  
Mortgage-backed securities – commercial
    
43,309
      
1,557
      
-
      
-
      
43,309
      
1,557
  
Corporate debt securities
    
536
      
6
      
5,476
      
435
      
6,012
      
441
  
Mutual funds and equity securities
    
128
      
2
      
113
      
9
      
241
      
11
  
Total
  $
341,755
     $
7,036
     $
13,429
     $
656
     $
355,184
     $
7,692
  
   
Less than 12 Months
    
12 Months or More
    
Total
  
December 31, 2015 (In thousands)
  
Fair
Value
    
Unrealized
Losses
    
Fair
Value
    
Unrealized
Losses
    
Fair
Value
    
Unrealized
Losses
  
Obligations of U.S. government-sponsored entities
   $
57,927
     $
275
     $
21,576
     $
263
     $
79,503
     $
538
  
Obligations of states and political subdivisions
    
30,426
      
123
      
8,276
      
90
      
38,702
      
213
  
Mortgage-backed securities – residential
    
118,978
      
851
      
21,723
      
638
      
140,701
      
1,489
  
Mortgage-backed securities – commercial
    
10,882
      
123
      
-
      
-
      
10,882
      
123
  
Corporate debt securities
    
204
      
6
      
5,155
      
794
      
5,359
      
800
  
Mutual funds and equity securities
    
481
      
21
      
264
      
48
      
745
      
69
  
Total
  $
218,898
     $
1,399
     $
56,994
     $
1,833
     $
275,892
     $
3,232