Note 3 - Summary of Accounts Receivable (Details) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015	Mar. 31, 2015	Dec. 31, 2014
Accounts receivable	$ 170,953	$ 173,995
Allowance for doubtful accounts	(5,157)	(4,849)	$ (1,478)	$ (1,898)
Accounts receivable, net	$ 165,796	$ 169,146