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STOCK BASED COMPENSATION - Assumptions used in Black-Scholes Model (Detail) (USD $)	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Weighted average fair value at grant date	$ 27.74	$ 22.29	$ 21.97	$ 20.08
Expected term (in years)	5 years 9 months	6 years	5 years 10 months 17 days	6 years
Expected volatility	26.27%	28.30%	27.05%	27.90%
Expected dividend yield	0.00%	0.00%	0.00%	0.00%
Risk free interest rate	1.02%	0.82%	1.00%	1.06%

The estimated measure of the percentage by which a share price is expected to fluctuate during a period. Volatility also may be defined as a probability-weighted measure of the dispersion of returns about the mean. The volatility of a share price is the standard deviation of the continuously compounded rates of return on the share over a specified period. That is the same as the standard deviation of the differences in the natural logarithms of the stock prices plus dividends, if any, over the period.

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