Note 14 - Capital Stock Share Repurchase Program (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended
	Jun. 30, 2019	Mar. 31, 2019	May 06, 2019	Mar. 20, 2019	Aug. 16, 2018
Third Quarter 2018 Repurchase Program
Capital Stock [Line Items]
Stock Repurchase Program, Authorized Amount					$ 100.0
First Quarter 2019 Repurchase Program
Capital Stock [Line Items]
Stock Repurchase Program, Authorized Amount				$ 150.0
Total of All Repurchase Programs
Capital Stock [Line Items]
Stock Repurchase Program, Authorized Amount				$ 250.0
Stock Repurchased During Period, Shares		1,546,674
Accelerated Share Repurchases, Final Price Paid Per Share		$ 20.54
Stock Repurchase Program, Remaining Authorized Repurchase Amount		$ 218.2
Subsequent Event | Total of All Repurchase Programs
Capital Stock [Line Items]
Stock Repurchased During Period, Shares	4,131,329
Accelerated Share Repurchases, Final Price Paid Per Share	$ 21.94
Stock Repurchase Program, Remaining Authorized Repurchase Amount			$ 127.7