Net Income (Loss) Per Share - Narrative (Detail) - $ / shares shares in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Shares of common stock at prices ranging, lower limit	$ 9.83	$ 7.14	$ 7.14
Shares of common stock at prices ranging, upper limit	$ 19.95	$ 19.95	$ 19.95
Employee stock options [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Share of common stock excluded from diluted net loss per share calculation (in shares)	0.7	1.1	1.3
Deferred stock units, performance-based stock units and restricted stock [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Share of common stock excluded from diluted net loss per share calculation (in shares)	0.9	0.7	0.5
Convertible Senior Debentures due 2018 [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Share of common stock excluded from diluted net loss per share calculation (in shares)	3.0	3.0	3.0