Note 5 - Stock-based Compensation - Tax Short-fall from Share-based Payment Arrangements (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Tax benefit/(short-fall) of tax deductions in excess of grant-date fair value		$ 17	$ (3,366)	$ (5,602)
Benefit of tax deductions on grant-date fair value		275	3,370	6,421
Total benefit of tax deductions		$ 292	$ 4	$ 819