Reconciliation of Net Income and Weighted-Average Shares of Common Stock Outstanding for Purposes of Calculating Basic and Diluted Earnings Per Share (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Numerator:
Net income	$ 8,301	$ 18,085
Denominator:
Weighted average shares outstanding - basic	43,873	44,448
Dilutive effect of share-based awards	513	429
Weighted average shares outstanding - diluted	44,386	44,877
Earnings per share:
Basic	$ 0.19	$ 0.41
Diluted	$ 0.19	$ 0.40