Note 5 - Supplemental Balance Sheet Information - Allowance for Doubtful Accounts (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Balance, beginning of year		$ 6,404	$ 9,546	$ 5,428
Provision for expected credit losses, net of recoveries (1)	[1]	500	(1,930)	8,188
Amounts written off and adjustments		(2,900)	(1,212)	(4,070)
Balance, end of year		$ 4,004	$ 6,404	$ 9,546

[1] The Company recorded bad debt expense (reversals) of $0.5 million, less than ($0.1) million and $5.3 million in 2020, 2019 and 2018, respectively, as part of the restructuring efforts (see Note 4) and was primarily due to the exiting of certain low-return businesses mainly in foreign locations.