Note 8 - Stock Repurchase Program - Stock Repurchase Program (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Shares repurchased (in shares)		645	1,051
Average price per share (in dollars per share)		$ 50.05	$ 39.19
Total amount		$ 32,286	$ 41,198