Note 6 - Capital Stock (Details Textual) - USD ($) $ / shares in Units, $ in Thousands			3 Months Ended
	Apr. 28, 2022	Jan. 20, 2022	Mar. 31, 2022	Mar. 31, 2021	Jan. 22, 2022
Stock Repurchase Program, Authorized Amount					$ 500,000
Stock Repurchase Program, Remaining Authorized Repurchase Amount			$ 276,000
Treasury Stock, Shares, Acquired (in shares)			382,000
Treasury Stock, Value, Acquired, Cost Method			$ 75,018	$ 5,239
Common Stock, Dividends, Per Share, Declared (in dollars per share)		$ 0.40
Dividends Payable, Date Declared		Jan. 20, 2022
Dividends Payable, Date to be Paid		Feb. 18, 2022
Dividends Payable, Date of Record		Feb. 04, 2022
Subsequent Event [Member]
Common Stock, Dividends, Per Share, Declared (in dollars per share)	$ 0.40
Dividends Payable, Date to be Paid	May 27, 2022
Dividends Payable, Date of Record	May 13, 2022