Computation of Earnings Per Share (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2015
Earnings Per Share [Abstract]
Net earnings									$ 95,274	$ 65,486	$ 65,975
Weighted average shares									62,576	61,366	61,219
Basic earnings per common share	$ 0.52	$ 0.36	$ 0.38	$ 0.26	$ 0.23	$ 0.24	$ 0.31	$ 0.28	$ 1.52	$ 1.07	$ 1.08
Net earnings									$ 95,274	$ 65,486	$ 65,975
Weighted average shares									62,576	61,366	61,219
Dilutive effect of common stock equivalents									1,931	1,543	1,367
Diluted weighted average common shares									64,507	62,909	62,586
Diluted earnings per common share	$ 0.50	$ 0.35	$ 0.37	$ 0.26	$ 0.23	$ 0.24	$ 0.30	$ 0.27	$ 1.48	$ 1.04	$ 1.05