Note 2 - Earnings per Common Share - Basic and Diluted Earnings Per Common Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020
Numerator:
Net income	$ 18,006	$ 13,718	$ 55,782
Denominator:
Basic earnings per common share - weighted-average shares (in shares)	82,758	82,214
Effect of dilutive stock options (in shares)	601	650
Diluted earnings per common share - weighted-average shares and assumed conversions (in shares)	83,359	82,864
Basic earnings per common share (in dollars per share)	$ 0.22	$ 0.17
Diluted earnings per common share (in dollars per share)	$ 0.22	$ 0.17