Stock Options and Other Equity-Based Incentive Instruments - Weighted-Average Assumptions Used to Determine Fair Value of Options Granted (Detail)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Assumptions used to value option grants [Abstract]
Average expected terms (years)	7 years	8 years 9 months 18 days	8 years 9 months 18 days
Volatility	56.20%	51.50%	51.20%
Annual rate of dividends	1.87%	2.36%	2.48%
Discount rate	1.26%	1.49%	1.70%