Note 5 - Capital Stock (Details Textual) - USD ($) $ / shares in Units, $ in Thousands			3 Months Ended		9 Months Ended
	Oct. 20, 2022	Jul. 20, 2022	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021	Jan. 22, 2020
Stock Repurchase Program, Authorized Amount		$ 500,000					$ 500,000
Stock Repurchase Program, Remaining Authorized Repurchase Amount			$ 551,000		$ 551,000
Treasury Stock, Shares, Acquired			349,000		1,710,000
Treasury Stock, Value, Acquired, Cost Method			$ 60,690	$ 50,336	$ 300,030	$ 136,917
Common Stock, Dividends, Per Share, Declared		$ 0.40
Subsequent Event [Member]
Common Stock, Dividends, Per Share, Declared	$ 0.40