Earnings (Loss) Per Share - Reconciliation of Numerators and Denominators Used in Computations of Both Basic and Diluted Earnings Per Share (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
Mar. 31, 2017	Mar. 31, 2016
Basic earnings (loss) per share computation:
Income (loss)	$ (9,759)	$ 39,201
Average common shares	90,709,802	91,567,119
Basic loss per share from continuing operations (in dollars per share)	$ (0.11)	$ 0.43
Diluted earnings (loss) per share computation:
Income (loss)	$ (9,759)	$ 39,201
Average common shares	90,709,802	91,567,119
Average common shares — diluted	90,709,802	92,168,303
Diluted earnings (loss) per share from continuing operations (in dollars per share)	$ (0.11)	$ 0.43
Stock options
Diluted earnings (loss) per share computation:
Stock option conversion	0	287,657
RSUs and PSUs
Diluted earnings (loss) per share computation:
Stock option conversion	0	313,527
Stock options
Diluted earnings (loss) per share computation:
Anti-dilutive securities excluded	1,760,843	1,403,295
RSUs and PSUs
Diluted earnings (loss) per share computation:
Anti-dilutive securities excluded	1,082,207	172,195

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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Amount after tax of income (loss) from continuing operations including portion attributable to the noncontrolling interest.

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The amount of net income (loss) from continuing operations per each share of common stock or unit outstanding during the reporting period.

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Additional shares included in the calculation of diluted EPS as a result of the potentially dilutive effect of share based payment arrangements using the treasury stock method.

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The average number of shares or units issued and outstanding that are used in calculating diluted EPS or earnings per unit (EPU), determined based on the timing of issuance of shares or units in the period.

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Number of [basic] shares or units, after adjustment for contingently issuable shares or units and other shares or units not deemed outstanding, determined by relating the portion of time within a reporting period that common shares or units have been outstanding to the total time in that period.

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