Share-Based Compensation - Summary of Assumptions Utilized in the Black-Scholes Model for Stock Options Granted (Detail) - Stock Option [Member] - $ / shares	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Weighted-average risk-free interest rate	0.54%	0.48%	0.27%
Expected term of option in years	3 years 4 months 17 days	2 years 11 months 23 days	2 years 11 months 23 days
Weighted-average volatility	44.30%	40.30%	34.10%
Dividend yield	3.40%	3.90%	9.10%
Weighted average grant date fair value per share	$ 6.34	$ 3.39	$ 0.79