Note 11 - Deferred Compensation Plan - Summary of Deferred Compensation Plan (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Deferred compensation plan assets	$ 51,759	$ 53,172
Deferred compensation plan liabilities	53,899	55,771
Other Long-term Assets [Member]
Deferred compensation plan assets	51,759	53,172
Accrued Compensation and Related Benefits [Member]
Deferred compensation plan liabilities	118	282
Other Long-term Liabilities [Member]
Deferred compensation plan liabilities	53,781	55,489
Cash Surrender Value [Member]
Deferred compensation plan assets	20,749	21,386
Mutual Funds and Money Market Funds, Fair Value [Member]
Deferred compensation plan assets	$ 31,010	$ 31,786