Note 13 - Stock Repurchase (Details Textual) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015	Feb. 29, 2016	Dec. 31, 2015	Jul. 31, 2013
Stock Repurchased and Retired During Period, Shares	0		0
Stock Repurchase Program, Authorized Amount					$ 50.0		$ 100.0
Stock Repurchase Program, Remaining Authorized Repurchase Amount						$ 5.9
Stock Repurchased During Period, Shares		300,000		600,000
Stock Repurchased During Period, Value		$ 13.6		$ 31.7
Repurchase Stock, Average Price Per Share, During Period		$ 47.93		$ 50.01