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 Determine Fair Value Options [Line Items]
Expected life (in years) used to determine the fair value of options granted	4 years 10 months 24 days	5 years	5 years 1 month 6 days
Risk-free interest rate used to determine the fair value of options granted	1.50%	0.70%	1.40%
Volatility factor used to determine the fair value of options granted	31.80%	35.00%	34.00%
Dividend yield used to determine the fair value of options granted	3.40%	3.60%	3.50%