Share-Based Compensation - Schedule of Weighted Average Option, Performance Share Fair Values and Assumptions (Detail) (USD $)	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Stock Option
Schedule of Weighted Average Assumptions for Fair Values of Stock Options[Line Items]
Weighted average fair value of option grants (in dollars per share)	$ 19.53	$ 12.85
Dividend yield	1.26%	1.57%
Volatility	30.36%	30.94%
Expected life (in years)	5 years 10 months 21 days	5 years 10 months 13 days
Performance Shares
Schedule of Weighted Average Assumptions for Fair Values of Stock Options[Line Items]
Weighted average fair value of option grants (in dollars per share)	$ 94.55	$ 50.45
Dividend yield	0.00%	0.00%
Volatility	26.41%	28.99%
Risk-free forward interest rate	0.65%	0.40%
Expected life (in years)	2 years 10 months 17 days	2 years 10 months 13 days
Minimum | Stock Option
Schedule of Weighted Average Assumptions for Fair Values of Stock Options[Line Items]
Risk-free forward interest rate	0.12%	0.17%
Maximum | Stock Option
Schedule of Weighted Average Assumptions for Fair Values of Stock Options[Line Items]
Risk-free forward interest rate	4.69%	4.10%