Note 19 - Stock-based Compensation (Tables)
 12 Months Ended
Dec. 31, 2016
Notes Tables  
Schedule of Share-based Compensation, Activity [Table Text Block]
 
 
Shares
Authorized for
Grant
 
Balance,
December 31, 2013
    
216,905
  
Shares authorized for grant under non-shareholder approved plans
    
47,368
  
Grants of RSUs
    
(16,456
)
Grants of PSUs
    
(71,184
)
Expiration of unexercised options
    
1,750
  
Forfeitures of RSAs and RSUs
    
2,560
  
Forfeitures of PSAs and PSUs
    
1,900
  
Balance,
December 31, 2014
    
182,843
  
Shares authorized for grant under shareholder approved plans
    
500,000
  
Grants of RSUs
    
(24,514
)
Grants of PSUs
    
(92,474
)
Expiration of unexercised options
    
3,180
  
Non-vesting PSAs*
    
25,929
  
Forfeitures of PSAs and PSUs
    
22,801
  
Balance,
December 31, 2015
    
617,765
  
Grants of RSUs
    
(33,142
)
Grants of PSUs
    
(45,346
)
Expiration of unexercised options
    
—
  
Non-vesting PSUs*
    
10,088
  
Forfeitures of PSUs
    
2,344
  
Forfeitures of RSUs
    
1,250
  
Balance,
December 31, 2016
    
552,959
  
Schedule of Share-based Compensation, Stock Options, Activity [Table Text Block]
 
 
For the Twelve Months Ended December 31,
 
 
 
2016
 
 
2015
 
 
2014
 
 
 
Shares
 
 
Weighted
Average
Exercise
Price
 
 
Weighted
Average
Grant Date
Fair Value
 
 
Shares
 
 
Weighted
Average
Exercise
Price
 
 
Weighted
Average
Grant Date
Fair Value
 
 
Shares
 
 
Weighted
Average
Exercise
Price
 
 
Weighted
Average
Grant Date
Fair Value
 
Options outstanding, beginning of period
   
290,853
     $
20.88
     $
4.85
      
447,966
     $
20.94
     $
4.75
      
591,086
     $
20.73
     $
4.70
  
Granted
   
—
      
—
      
—
      
—
     $
—
     $
—
      
—
     $
—
     $
—
  
Assumed in the CBH Merger
    
—
      
—
      
—
      
181,256
     $
17.73
     $
—
      
—
     $
—
     $
—
  
Expired
   
—
      
—
      
—
      
(3,180
)
   $
21.33
     $
4.84
      
(1,750
)
   $
22.31
     $
4.99
  
Exercised
   
(105,830
)
   $
20.61
      
7.32
      
(335,189
)
   $
19.25
     $
4.62
      
(141,370
)
   $
20.06
     $
4.51
  
Options outstanding, end of period
   
185,023
      
21.04
      
4.88
      
290,853
     $
20.88
     $
4.85
      
447,966
     $
20.94
     $
4.75
  
Schedule of Share-based Compensation, Shares Authorized under Stock Option Plans, by Exercise Price Range [Table Text Block]
 
    
 
Options Outstanding
 
 
Options Exercisable
 
Range of Exercise
Prices
 
Options
Outstanding
 
 
Remaining
Contractual
Life (in years)
 
 
Shares
Exercisable
 
 
Remaining
Contractual
Life (in years)
 
 
Weighted Average
Exercise
Price*
 
$10.36
to
$17.15
    
1,383
      
2.21
     
1,383
      
2.21
    $
12.58
  
$17.16
to
$18.30
    
87,725
      
2.64
     
87,725
      
2.64
    $
18.27
  
$18.31
to
$20.17
    
563
      
7.05
     
563
      
7.05
    $
18.33
  
$20.18
to
$22.64
    
23,500
      
0.66
     
23,500
      
0.66
    $
22.00
  
$22.65
to
$23.78
    
338
      
0.96
     
338
      
0.96
    $
23.28
  
$23.79
to
$24.27
    
71,514
      
1.63
     
71,514
      
1.63
    $
24.27
  
 
 
 
    
185,023
      
2.00
     
185,023
      
2.00
    $
21.03
  
Schedule of Nonvested Share Activity [Table Text Block]
 
 
For the Twelve Months Ended December 31,
 
 
 
2016
 
 
2015
 
 
2014
 
 
 
Shares
 
 
Weighted
Average
Grant Date
Fair Value
 
 
Shares
 
 
Weighted
Average
Grant Date
Fair Value
 
 
Shares
 
 
Weighted
Average
Grant Date
Fair Value
 
Unvested options, beginning of period
   
—
     $
—
      
—
     $
—
      
30,146
     $
4.42
  
Granted
   
—
     $
—
      
—
     $
—
      
—
     $
—
  
Assumed in CBH Merger
    
—
     $
—
      
181,256
     $
12.94
      
—
     $
—
  
Vested
   
—
     $
—
      
(181,256
)
   $
12.94
      
(30,146
)
   $
4.42
  
Forfeited
   
—
     $
—
      
—
     $
—
      
—
     $
—
  
Unvested options, end of period
   
—
     $
—
      
—
     $
—
      
—
     $
—
  
Schedule of Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Grant Date Intrinsic Value [Table Text Block]
 
 
For the Twelve Months Ended December 31,
 
(dollars in thousands)
 
2016
 
 
2015
 
 
2014
 
Proceeds from strike price of value of options exercised
  $
2,181
     $
6,452
     $
2,836
  
Related tax benefit recognized
   
256
      
515
      
378
  
Proceeds of options exercised
  $
2,437
     $
6,967
     $
3,214
  
                         
Intrinsic value of options exercised
  $
1,125
     $
3,615
     $
1,288
  
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding and Exercisable [Table Text Block]
 
 
As of December 31,
 
 
 
2015
 
 
2014
 
 
201
3
 
 
 
Options
Outstanding
 
 
Exercisable
Options
 
 
Options
Outstanding
 
 
Exercisable
Options
 
 
Options
Outstanding
 
 
Exercisable
Options
 
Number
   
185,023
      
185,023
      
290,853
      
290,853
      
447,966
      
447,966
  
Weighted average exercise price
  $
21.03
     $
21.03
     $
20.88
     $
20.88
     $
20.94
     $
20.94
  
Aggregate intrinsic value
  $
3,907,758
     $
3,907,758
     $
2,280,288
     $
2,280,288
     $
4,640,917
     $
4,640,917
  
Weighted average contractual term (in years)
    
2.0
     
2.0
     
2.9
     
2.9
     
2.7
     
2.7
 
Schedule of Nonvested Restricted Stock Units Activity [Table Text Block]
 
 
Twelve Months Ended
December 31, 2016
 
 
Twelve Months Ended
December 31, 2015
 
 
Twelve Months Ended
December 31,
2014
 
 
 
Number of
Shares
 
 
Weighted
Average
Grant Date
Fair Value
 
 
Number of
Shares
 
 
Weighted
Average
Grant Date
Fair Value
 
 
Number of
Shares
 
 
Weighted
Average
Grant Date
Fair Value
 
Beginning balance
   
42,802
     $
28.58
      
46,281
     $
23.17
      
54,156
     $
19.36
  
Granted
    
33,142
     $
29.67
      
24,514
     $
29.83
      
16,456
     $
28.88
  
Vested
    
(15,832
)
   $
27.14
      
(27,993
)
   $
20.73
      
(21,771
)
   $
18.21
  
Forfeited
    
(1,250
)
   $
29.12
      
—
     $
—
      
(2,560
)
   $
21.48
  
Ending balance
    
58,862
     $
29.57
      
42,802
     $
28.58
      
46,281
     $
23.17
  
Schedule of Nonvested Performance-based Units Activity [Table Text Block]
 
 
Twelve Months Ended
December 31, 2016
 
 
Twelve Months Ended
December 31, 2015
 
 
Twelve Months Ended
December 31, 2014
 
 
 
Number of Shares
 
 
Weighted
Average
Grant Date Fair Value
 
 
Number
of
Shares
 
 
Weighted
Average
Grant Date Fair Value
 
 
Number
of
Shares
 
 
Weighted
Average
Grant Date Fair Value
 
Beginning balance
   
216,820
     $
15.07
      
217,318
     $
13.41
      
204,980
     $
11.90
  
Granted
    
45,346
     $
28.34
      
92,474
     $
16.42
      
71,184
     $
15.05
  
Vested
    
(56,890
)
   $
13.38
      
(44,242
)
   $
11.80
      
(56,946
)
   $
10.07
  
Non-vesting*
    
(10,088
)
   $
13.38
      
(25,929
)
   $
11.80
      
—
     $
—
  
Forfeited
    
(2,344
)
   $
15.37
      
(22,801
)
   $
14.75
      
(1,900
)
   $
12.32
  
Ending balance
    
192,844
     $
18.77
      
216,820
     $
15.07
      
217,318
     $
13.41