Note 19 - Stock-based Compensation - Remaining Shares Authorized to Be Granted for Options, Restricted Stock Awards and Performance Stock Awards (Details) - shares
 12 Months Ended
Dec. 31, 2016
Dec. 31, 2015
Dec. 31, 2014
Balance (in shares)     216,905
Options, RSAs or PSAs [Member]      
Balance (in shares) 617,765 182,843  
Shares authorized for grant (in shares)   500,000 47,368
Expiration of unexercised options (in shares) 3,180 1,750
Balance (in shares) 552,959 617,765 182,843
Restricted Stock Units (RSUs) [Member]      
Grants (in shares) (33,142) (24,514) (16,456)
Forfeitures (in shares) 1,250    
Performance Stock Awards [Member]      
Balance (in shares) 216,820 217,318 204,980
Grants (in shares) (45,346) (92,474) (71,184)
Forfeitures (in shares) 2,344 22,801 1,900
Balance (in shares) 192,844 216,820 217,318
Non-vesting (in shares) [1] 10,088 25,929 [2]
Options, RSAs or RSUs [Member]      
Forfeitures (in shares)     2,560
Options, PSAs or PSUs [Member]      
Forfeitures (in shares)   22,801 1,900
[1] Non-vesting PSAs represent PSAs that did not meet their performance criteria, and were therefore cancelled. The associated expense, however, was incurred over the vesting period.
[2] Non-vesting PSAs represent PSAs that did not meet their performance criteria, and were therefore cancelled and are available for future grant.