Note 2 - Net Income Per Share Net Income (Loss) Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands		3 Months Ended
		Mar. 31, 2020	Mar. 31, 2019
Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Line Items]
Net income (loss)—diluted		$ 140,461	$ 170,957
Dilutive effect of share-based compensation arrangements	[1]	1,658	4,806
Adjusted average common shares outstanding—diluted		201,819	218,343
Net income (loss) per share—diluted		$ 0.70	$ 0.78
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Net income (loss) - basic		$ 140,461	$ 170,957
Average common shares outstanding - basic	[2]	200,161	213,537
Net income (loss) per share - basic		$ 0.70	$ 0.80
Stock Compensation Plan
Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Line Items]
Shares of common stock equivalents		132	169

[1] The following number of shares of our common stock equivalents issued under our share-based compensation arrangements were not included in the calculation of diluted net income per share because they were anti-dilutive:   Three Months Ended
March 31, (In thousands) 2020   2019 Shares of common stock equivalents 132
  169

[2] Includes the impact of fully vested shares under our share-based compensation programs.