Note 9 - Segment Information - Revenues by Geographical Areas (Details) - USD ($)
$ in Thousands
3 Months Ended 9 Months Ended
Sep. 30, 2016
Sep. 30, 2015
Sep. 30, 2016
Sep. 30, 2015
UNITED STATES        
Revenues $ 68,462 $ 106,300 $ 181,677 $ 264,034
All Foreign Countries [Member]        
Revenues 844 754 2,143 1,705
Revenues $ 69,306 $ 107,054 $ 183,820 $ 265,739