Note 8 - Stockholders' Equity (Tables)
 12 Months Ended
Mar. 31, 2017
Notes Tables  
Dividends Declared [Table Text Block]
 
 
Year E
nded March 31,
 
 
 
2017
 
 
201
6
 
 
201
5
 
First quarter
   $
0.16
     $
0.16
     $
0.15
  
Second quarter
    
0.16
      
0.16
      
0.15
  
Third quarter
    
0.16
      
0.16
      
0.16
  
Fourth quarter
    
0.16
      
0.16
      
0.16