Note 14 - Capital Stock (Details) - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended			3 Months Ended			12 Months Ended
	Mar. 31, 2016	Aug. 31, 2015	Jun. 30, 2015	Jun. 30, 2017	Mar. 31, 2016	Jun. 30, 2015	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Aug. 09, 2017	Jun. 29, 2016	Jun. 18, 2015
Class of Stock [Line Items]
Payments for Repurchase of Common Stock							$ 6	$ 100,188	$ 202,000
Convertible Senior Notes Due 2017 [Member]
Class of Stock [Line Items]
Debt Conversion, Converted Instrument, Shares Issued			28,400,000
Convertible Debt, Termination of Capped Call Transaction, Number of Shares Received			2,300,000
Convertible Debt [Member]
Class of Stock [Line Items]
Debt Conversion, Converted Instrument, Shares Issued	17,000,000
Convertible Debt, Termination of Capped Call Transaction, Number of Shares Received	200,000
First Quarter 2016 Repurchase Program [Member]
Class of Stock [Line Items]
Stock Repurchased During Period, Shares					9,400,000
Payments for Repurchase of Common Stock					$ 100,200
Accelerated Share Repurchases, Final Price Paid Per Share					$ 10.62
Stock Repurchase Program, Remaining Authorized Repurchase Amount							$ 0
Second Quarter 2016 Repurchase Program [Member]
Class of Stock [Line Items]
Stock Repurchased During Period, Shares				380
Accelerated Share Repurchases, Final Price Paid Per Share				$ 15.59
Stock Repurchase Program, Authorized Amount											$ 125,000
Third Quarter 2017 Repurchase Program [Member]
Class of Stock [Line Items]
Stock Repurchased During Period, Shares							0
Stock Repurchase Program, Authorized Amount										$ 50,000
Second Quarter 2015 Repurchase Program [Member]
Class of Stock [Line Items]
Stock Repurchased During Period, Shares		1,800,000				9,200,000
Accelerated Share Repurchases, Final Price Paid Per Share		$ 18.32
Stock Repurchase Program, Authorized Amount												$ 202,000