Earnings Per Share - Calculation of Basic and Diluted Earnings per Share (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2020	Dec. 31, 2019
Earnings Per Share [Abstract]
Net income	$ 106,478	$ 79,195	$ 200,122	$ 147,172
Weighted-average number of basic shares outstanding during the period	25,225	25,065	25,162	24,979
Dilutive effect of RSUs after application of treasury stock method	226	370	307	504
Weighted-average number of diluted shares outstanding during the period	25,451	25,435	25,469	25,483
Basic earnings per share	$ 4.22	$ 3.16	$ 7.95	$ 5.89
Diluted earnings per share	$ 4.18	$ 3.11	$ 7.86	$ 5.78