Note 5 - Stock-Based Compensation (Details) - Tax Short-fall from Share-based Payment Arrangements - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Tax Short-fall from Share-based Payment Arrangements [Abstract]
Short-fall of tax deductions in excess of grant-date fair value	$ (1,224)	$ 50	$ (5,619)	$ (1,177)
Benefit of tax deductions on grant-date fair value	1,554	$ (50)	6,146	$ 1,177
Total benefit of tax deductions	$ 330		$ 527