Note 2 - Summary of Significant Accounting Policies - Basic and Diluted Earnings Per Share Computation (Details) - shares shares in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Weighted average basic shares outstanding (in shares)	107,329	109,375	109,987
Effect of common stock equivalents (in shares)	978	1,053	1,062
Weighted average shares outstanding – diluted (in shares)	108,307	110,428	111,049