Stock-Based Compensation - Weighted Average Fair Value Per Share of Options Granted (Detail) (Stock Options [Member])	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Weighted-average volatility	41.00%	46.00%	45.00%
Expected dividend yield
Expected life (in years)	4 years 9 months	4 years 9 months	6 years 3 months
Minimum [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Risk-free interest rate	0.68%	0.61%	1.58%
Maximum [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Risk-free interest rate	1.37%	0.82%	3.05%