Note 2 - Earnings Per Share (Details Textual) - shares shares in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Incremental Common Shares Attributable to Share-based Payment Arrangements, Total (in shares)	1.1	1.0	1.1	1.0