Note 2 - Earnings Per Share (Details Textual) - shares shares in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Incremental Common Shares Attributable to Share-based Payment Arrangements, Total (in shares)	1.3	1.1	1.2	1.0