Earnings Per Share - Anti-dilutive Potential Shares of Common Stock Excluded from Computation of Earnings Per Share (Detail) - shares shares in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive potential shares of common stock excluded from computation of earnings per share, amount	3,552	2,153
Common stock related to employee equity awards [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive potential shares of common stock excluded from computation of earnings per share, amount	1,583	211
4.75% Convertible Subordinated Notes [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive potential shares of common stock excluded from computation of earnings per share, amount	1,969	1,942
Convertible debt interest rate	4.75%	4.75%