Note 3 - Equity Investment - Summary of Financial Information for Matrix (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016	Dec. 31, 2016
Current assets	$ 286,223		$ 286,223		$ 288,103
Current liabilities	238,621		238,621		227,796
Revenue	407,983	$ 398,119	807,477	$ 780,154
Operating income	5,999	6,713	12,786	15,017
Net income (loss)	3,915	$ 4,623	(411)	$ 6,858
Matrix [Member]
Current assets	43,479		43,479		28,589
Long-term assets	604,598		604,598		614,841
Current liabilities	35,236		35,236		25,791
Long-term liabilities	274,426		274,426		$ 281,348
Revenue	60,852		116,707
Operating income	5,942		6,950
Net income (loss)	$ 1,619		$ (238)