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, 2020	Mar. 31, 2019	Dec. 31, 2019
Numerator:
Net income	$ 13,718	$ 13,546	$ 47,525
Denominator:
Basic earnings per common share - weighted-average shares (in shares)	54,809	54,553
Effect of dilutive stock options (in shares)	434	493
Diluted earnings per common share - weighted-average shares and assumed conversions (in shares)	55,243	55,046
Basic earnings per common share (in dollars per share)	$ 0.25	$ 0.25
Diluted earnings per common share (in dollars per share)	$ 0.25	$ 0.25