Net Earnings Per Share ("EPS") - Reconciliation of Denominators of Basic and Diluted EPS Calculations (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Numerator:
Net earnings	$ 38,906	$ 27,132	$ 119,252	$ 116,457
Denominator:
Weighted average shares used to compute basic EPS	35,077	35,512	35,123	35,631
Dilutive potential common shares due to dilutive RSUs, net of tax effect	271	356	295	396
Weighted average shares used to compute diluted EPS	35,348	35,868	35,418	36,027
Net earnings per share:
Basic	$ 1.11	$ 0.76	$ 3.40	$ 3.27
Diluted	$ 1.10	$ 0.76	$ 3.37	$ 3.23