Note 7 - Earnings Per Share - Shares Used in the Earnings Per Share Computations (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2017	Dec. 31, 2016
Net earnings	$ 48,847	$ 7,467	$ 64,710	$ 26,309
Income allocated to participating securities	(41)	(7)	(50)	(22)
Income available to common shareholders	$ 48,806	$ 7,460	$ 64,660	$ 26,287
Basic (in shares)	37,449	37,308	37,412	37,294
Basic (in dollars per share)	$ 1.30	$ 0.20	$ 1.73	$ 0.70
Net income	$ 48,847	$ 7,467	$ 64,710	$ 26,309
Income available to common shareholders	$ 48,806	$ 7,460	$ 64,660	$ 26,287
Weighted-average shares outstanding – basic (in shares)	37,449	37,308	37,412	37,294
Dilutive effect of stock options and restricted stock units (in shares)	477	170	404	181
Diluted (in shares)	37,926	37,478	37,816	37,475
Diluted (in dollars per share)	$ 1.29	$ 0.20	$ 1.71	$ 0.70