Earnings Per Share - Calculation of Basic and Diluted Earnings per Share (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Mar. 31, 2021	Mar. 31, 2020
Earnings Per Share [Abstract]
Net income	$ 120,344	$ 80,577	$ 320,466	$ 227,749
Weighted-average number of basic shares outstanding during the period	24,935	25,078	25,026	25,012
Dilutive effect of RSUs after application of treasury stock method	231	400	281	469
Weighted-average number of diluted shares outstanding during the period	25,166	25,478	25,307	25,481
Basic earnings per share	$ 4.83	$ 3.21	$ 12.81	$ 9.11
Diluted earnings per share	$ 4.78	$ 3.16	$ 12.66	$ 8.94