Note 16 - Selected Quarterly Financial Data (Unaudited) - Unaudited Quarterly Financial Data (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended																12 Months Ended
	Dec. 31, 2019	[1]	Sep. 30, 2019	[2]	Jun. 30, 2019	[3]	Mar. 31, 2019	[4]	Dec. 31, 2018	[1]	Sep. 30, 2018	[2]	Jun. 30, 2018	[4]	Mar. 31, 2018	[4]	Dec. 31, 2019		Dec. 31, 2018		Dec. 31, 2017
Revenues	$ 309,502		$ 308,789		$ 318,740		$ 276,904		$ 333,998		$ 339,679		$ 335,030		$ 324,861		$ 1,213,935	[5]	$ 1,333,568	[5]	$ 1,359,019	[5]
Gross profit	63,711		66,792		67,437		48,295		61,696		72,673		71,053		61,504		246,235	[5]	266,926	[5]	284,812	[5]
Operating income (loss)	(3,361)		14,649		459		(774)		(1,002)		13,009		14,459		3,181		10,973	[5]	29,647	[5]	(43,520)	[5]
Net income (loss)	$ (13,659)		$ 6,349		$ (8,147)		$ (3,991)		$ (2,776)		$ 141		$ 7,198		$ (1,476)		$ (19,448)		$ 3,087		$ (66,582)
Basic (in dollars per share)	$ (0.47)		$ 0.20		$ (0.27)		$ (0.13)		$ (0.08)		$ (0.01)		$ 0.24		$ (0.06)		$ (0.67)		$ 0.09		$ (2.09)
Diluted (in dollars per share)	$ (0.47)		$ 0.19		$ (0.27)		$ (0.13)		$ (0.08)		$ (0.01)		$ 0.24		$ (0.06)		$ (0.67)		$ 0.09		$ (2.09)

[1] Includes pre-tax expenses of $13.9 million related to our restructuring efforts (see Note 4).

[2] Includes pre-tax expenses of $7.4 million related to our restructuring efforts (see Note 4).

[3] Includes pre-tax expenses of $6.5 million related to our restructuring efforts (see Note 4).

[4] Includes pre-tax expenses of $5.2 million related to our restructuring efforts (see Note 4).

[5] Attributed to the country of origin.