Note 11 - Stockholders' Equity and Stock Incentive Plans - Share Repurchases (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands		12 Months Ended
		Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Shares repurchased (2) (in shares)	[1],[2]	1,087	1,853	1,198
Total cost, including brokerage fees	[2]	$ 28,045	$ 59,570	$ 31,927
Average repurchase price per share (3) (in dollars per share)	[2],[3]	$ 25.80	$ 32.14	$ 26.64

[1] All shares repurchased have been retired and constitute authorized but unissued shares.

[2] Shares repurchased reflect repurchases settled during the twelve months ended December 31, 2019, 2018 and 2017. These amounts exclude repurchases, if any, traded but not yet settled on or before December 31, 2019, 2018 and 2017.

[3] Figures in the table may not recalculate exactly due to rounding. Average repurchase price per share is calculated based on unrounded numbers.