Summary of Basic and Diluted Earnings Per Share (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
Mar. 31, 2019	Mar. 31, 2018
Earning per share reconciliation
Net (loss) income	$ (28,717)	$ 12,200
Weighted-average common shares outstanding (in shares)	78,584	78,236
(Loss) earnings per share, basic (in dollars per share)	$ (0.37)	$ 0.16
Net (loss) income	$ (28,717)	$ 12,200
Effect of dilutive securities (in shares)	0	4,866
Weighted-average common shares outstanding, assuming dilution (in shares)	78,584	83,102
(Loss) earnings per share, diluted (in dollars per share)	$ (0.37)	$ 0.15
Outstanding anti-dilutive stock options and RSUs (in shares)	5,563	397
Stock Options
Earning per share reconciliation
Weighted-average effect of dilutive securities (in shares)	0	3,119
RSUs
Earning per share reconciliation
Weighted-average effect of dilutive securities (in shares)	0	1,747

Securities (including those issuable pursuant to contingent stock agreements) that could potentially dilute basic earnings per share (EPS) or earnings per unit (EPU) in the future that were not included in the computation of diluted EPS or EPU because to do so would increase EPS or EPU amounts or decrease loss per share or unit amounts for the period presented.

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