STOCK-BASED COMPENSATION (Details) (USD $) Share data in Thousands, except Per Share data, unless otherwise specified	3 Months Ended		12 Months Ended
	Mar. 31, 2013	Mar. 31, 2012	Dec. 31, 2012
Stock-based compensation
Stock-based compensation plans	2
Compensation expense on share-based plans	$ 7,000,000	$ 6,600,000
Stock options
Stock-based compensation
Excess tax benefit realized for tax deductions from non-qualified stock option exercises and disqualifying dispositions of incentive stock options	200,000	500,000
Weighted-average assumptions used to estimate the fair value of options granted
Dividend yield (as a percent)	0.00%	0.00%
Expected volatility (as a percent)	47.80%	48.30%
Risk-free interest rate (as a percent)	0.90%	0.90%
Expected term	5 years 4 months 24 days	5 years 6 months
Stock Options, Number of Shares
Balance at the beginning of the period (in shares)	14,000
Granted (in shares)	636
Exercised (in shares)	(117)
Cancelled or forfeited (in shares)	(113)
Balance at the end of the period (in shares)	14,406		14,000
Vested and expected to vest in the future at the end of the period (in shares)	13,999
Exercisable at the end of the period (in shares)	11,037
Stock options, Weighted-Average Exercise Price Per Share
Balance at the beginning of the period (in dollars per share)	$ 12.12
Granted (in dollars per shares)	$ 47.36
Exercised (in dollars per share)	$ 20.27
Cancelled or forfeited (in dollars per share)	$ 25.55
Balance at the end of the period (in dollars per share)	$ 13.51		$ 12.12
Vested and expected to vest in the future at the end of the period (in dollars per share)	$ 12.75
Exercisable at the end of the period (in dollars per share)	$ 8.36
Weighted-Average Remaining Contractual Term
Balance at the beginning of the period	4 years 1 month 6 days		4 years 1 month 6 days
Balance at the end of the period	4 years 1 month 6 days		4 years 1 month 6 days
Vested and expected to vest in the future at the end of the period	4 years
Exercisable at the end of the period	3 years 1 month 6 days
Aggregate Intrinsic Value
Balance at the beginning of the period	572,530,000
Balance at the end of the period	497,761,000		572,530,000
Vested and expected to vest in the future at the end of the period	493,506,000
Exercisable at the end of the period	$ 434,897,000