Note 9 - Retirement Plans and Postretirement Benefit Plans (Tables)
 12 Months Ended
Dec. 31, 2016
Notes Tables  
Schedule of Changes in Accumulated Post Employment Benefit Obligations for Interest Payable and Other Liabilities [Table Text Block]
 
 
2016
 
 
2015
 
APBO
 
$
3,745
 
   $
3,406
 
Unrecognized net gain (loss)
 
 
(267
)
    
(67
 )
Accrued benefit cost at fiscal year end
 
$
3,478
 
   $
3,339
 
Schedule of Net Benefit Costs [Table Text Block]
 
 
2016
 
 
2015
 
 
2014
 
Service cost
 
$
128
 
   $
173
    $
135
 
Interest cost
 
 
142
 
    
143
     
144
 
Prior service costs
 
 
-
 
    
-
     
2
 
Amortization of gains
 
 
-
 
    
27
     
1
 
Net postretirement benefit expense
 
$
270
 
   $
343
    $
282
 
Changes in Projected Benefit Obligations, Fair Value of Plan Assets, and Funded Status of Plan [Table Text Block]
 
 
Postretirement Death Benefit Obligations
 
 
Postretirement Health Care Benefits
 
 
 
2016
 
 
2015
 
 
2016
 
 
2015
 
                                 
Change in benefit obligation
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Benefit obligation at beginning of year
 
$
5,952
 
    
5,892
 
 
$
3,406
 
   $
3,865
 
Service cost
 
 
9
 
    
9
 
 
 
128
 
    
173
 
Interest cost
 
 
233
 
    
217
 
 
 
142
 
    
143
 
Actuarial loss (gain)
 
 
(9
)
    
(166
 )
 
 
200
 
    
(686
 )
Benefits paid, net of participants' contributions
 
 
-
 
    
-
 
 
 
(131
)
    
(89
 )
Benefit obligation at end of year
 
$
6,185
 
   $
5,952
 
 
$
3,745
 
   $
3,406
 
                                 
Change in accrued benefit cost
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Accrued benefit cost at beginning of year
 
$
4,793
 
   $
4,405
 
 
$
3,339
 
   $
3,085
 
Service cost
 
 
9
 
    
9
 
 
 
128
 
    
173
 
Interest cost
 
 
233
 
    
217
 
 
 
142
 
    
143
 
Amortization
 
 
161
 
    
162
 
 
 
-
 
    
-
 
Employer contributions
 
 
-
 
    
-
 
 
 
(131
)
    
(89
 )
Net gain
 
 
-
 
    
-
 
 
 
-
 
    
27
 
Accrued benefit cost at end of year
 
$
5,196
 
   $
4,793
 
 
$
3,478
 
   $
3,339
 
                                 
Change in plan assets
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Fair value of plan assets at beginning of year
 
$
-
 
   $
-
 
 
$
-
 
   $
-
 
Employer contributions
 
 
-
 
    
-
 
 
 
131
 
    
89
 
Plan participants' contributions
 
 
-
 
    
-
 
 
 
74
 
    
55
 
Benefits paid during year
 
 
-
 
    
-
 
 
 
(205
)
    
(144
 )
Fair value of plan assets at end of year
 
$
-
 
   $
-
 
 
$
-
 
   $
-
 
                                 
Funded status at end of year
 
$
(6,185
)
   $
(5,952
 )
 
$
(3,745
)
   $
(3,406
 )
Schedule of Amounts Recognized in Balance Sheet [Table Text Block]
 
 
Postretirement Death Benefit Obligations
 
 
Postretirement Health Care Benefits
 
 
 
2016
 
 
2015
 
 
2016
 
 
2015
 
Assets
 
$
-
 
    
-
 
 
$
-
 
   $
-
 
Liabilities
 
 
6,185
 
    
5,952
 
 
 
3,745
 
    
3,406
 
Total
 
$
6,185
 
   $
5,952
 
 
$
3,745
 
   $
3,406
 
Schedule of Amounts Recognized in Other Comprehensive Income (Loss) [Table Text Block]
 
 
Postretirement Death Benefit Obligations
 
 
Postretirement Health Care Benefits
 
 
 
2016
 
 
2015
 
 
2016
 
 
2015
 
Net loss (gain)
 
$
(326
)
    
(317
 )
 
$
267
 
   $
67
 
Transition obligation (asset)
 
 
-
 
    
-
 
 
 
-
 
    
-
 
Prior service cost (credit)
 
 
1,315
 
    
1,476
 
 
 
-
 
    
-
 
Total included in AOCI
 
$
989
 
   $
1,159
 
 
$
267
 
   $
67
 
Schedule of Expected Benefit Payments [Table Text Block]
Year
    
Postretirement Death Benefit Obligations
    
Postretirement Health Care Benefits
  
2017
     $
286,000
    $
141,000
 
2018
      
298,000
     
160,000
 
2019
      
309,000
     
170,000
 
2020
      
319,000
     
177,000
 
2021
      
340,000
     
183,000
 
2022
-
2026
      
1,816,000
     
998,000