Note 14 - Capital Stock Share Repurchase Programs (Details) $ / shares in Units, $ in Millions	3 Months Ended		6 Months Ended	12 Months Ended
	Mar. 31, 2020 $ / shares shares	Jun. 30, 2017 $ / shares shares	Jun. 30, 2018 $ / shares shares	Dec. 31, 2019 USD ($) $ / shares shares	Feb. 25, 2020 USD ($)	Feb. 13, 2020 USD ($)	Aug. 14, 2019 USD ($)	Mar. 20, 2019 USD ($)	Aug. 16, 2018 USD ($)	Aug. 09, 2017 USD ($)	Jun. 29, 2016 USD ($)
3Q18 Repurchase Program
Class of Stock [Line Items]
Stock Repurchase Program, Authorized Amount									$ 100.0
1Q19 Repurchase Program
Class of Stock [Line Items]
Stock Repurchase Program, Authorized Amount								$ 150.0
Total of 3Q18 and 1Q19 Repurchase Programs
Class of Stock [Line Items]
Stock Repurchase Program, Authorized Amount								$ 250.0
Stock Repurchased During Period, Shares | shares				11,258,574
Accelerated Share Repurchases, Final Price Paid Per Share | $ / shares				$ 22.22
Percent of Reduction in Shares Outstanding				0.053
Stock Repurchase Program, Remaining Authorized Repurchase Amount				$ 0.0
3Q19 Repurchase Program
Class of Stock [Line Items]
Stock Repurchase Program, Authorized Amount							$ 200.0
Stock Repurchased During Period, Shares | shares				2,195,661
Accelerated Share Repurchases, Final Price Paid Per Share | $ / shares				$ 22.79
Stock Repurchase Program, Remaining Authorized Repurchase Amount				$ 150.0
3Q17 Repurchase Program
Class of Stock [Line Items]
Stock Repurchase Program, Authorized Amount										$ 50.0
Stock Repurchased During Period, Shares | shares			3,022,856
Accelerated Share Repurchases, Final Price Paid Per Share | $ / shares			$ 16.56
2Q16 Repurchase Program
Class of Stock [Line Items]
Stock Repurchase Program, Authorized Amount											$ 125.0
Stock Repurchased During Period, Shares | shares		380
Accelerated Share Repurchases, Final Price Paid Per Share | $ / shares		$ 15.59
Subsequent Event | 1Q20 Repurchase Program
Class of Stock [Line Items]
Stock Repurchase Program, Authorized Amount						$ 275.0
Subsequent Event | Total of 3Q19 and 1Q20 Repurchase Programs
Class of Stock [Line Items]
Stock Repurchase Program, Authorized Amount						$ 475.0
Stock Repurchased During Period, Shares | shares	2,738,462
Accelerated Share Repurchases, Final Price Paid Per Share | $ / shares	$ 24.03
Stock Repurchase Program, Remaining Authorized Repurchase Amount					$ 359.2