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		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Basic earnings (loss) per share computation:
Income (loss) from continuing operations	$ 14,526	$ 20,233	$ 87,098	$ (26,899)
Average common shares	90,423,466	93,254,547	91,076,741	93,950,693
Basic loss per share from continuing operations (in dollars per share)	$ 0.16	$ 0.22	$ 0.96	$ (0.29)
Diluted earnings (loss) per share computation:
Income (loss) from continuing operations	$ 14,526	$ 20,233	$ 87,098	$ (26,899)
Average common shares	90,423,466	93,254,547	91,076,741	93,950,693
Average common shares — diluted	90,965,375	93,816,178	91,694,838	93,950,693
Diluted earnings (loss) per share from continuing operations (in dollars per share)	$ 0.16	$ 0.22	$ 0.95	$ (0.29)
Common Stock
Diluted earnings (loss) per share computation:
Stock option conversion	225,789	202,974	246,096	0
Anti-dilutive securities excluded	1,184,449	2,624,204	1,292,766	2,979,348
RSUs and PSUs
Diluted earnings (loss) per share computation:
Stock option conversion	316,120	358,657	372,001	0
Anti-dilutive securities excluded	4,410	755	1,481	302,022