Note 13 - Stock Repurchase (Details Textual) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015	Feb. 29, 2016	Dec. 31, 2015	Jul. 31, 2013
Stock Repurchased and Retired During Period, Shares	0	100,000	0	400,000
Stock Repurchase Program, Authorized Amount					$ 50.0		$ 100.0
Stock Repurchase Program, Remaining Authorized Repurchase Amount						$ 5.9
Stock Repurchased and Retired During Period, Value		$ 7.7		$ 18.1
Repurchase Stock, Average Price Per Share, During Period		$ 52.19		$ 51.70