Capital Stock - Risk-Free Rate Based on U S Treasury Yield Curve (Detail) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012
Equity [Abstract]
Expected volatility	33.60%	34.94%
Expected dividend yields	0.99%	0.82%
Expected term (in years)	5 years 6 months	5 years 6 months
Risk-free rate	0.79%	0.78%
Weighted-average grant-date fair value	$ 23.18	$ 26.41