EQUITY AND SHARE-BASED COMPENSATION (Tables)

3 Months Ended

Mar. 31, 2014

EQUITY AND SHARE-BASED COMPENSATION

Schedule of assumptions used to determine the fair value of options as of the grant date

	Three months endedMarch 31, 2013
	Black-Scholes	Binomial
Risk-free interest rate	1.02% – 1.13%	0.08% – 2.02%
Expected stock price volatility	36.35% – 36.50%	36.40% – 36.50%
Expected dividend yield	—	—
Expected option life (in years)	6.25	—
Contractual life (in years)	—	14
Fair value	$31.33 – $34.74	$16.12 – $30.34

Summary of the weighted average fair value of stock options granted, the total intrinsic value of stock options exercised and the fair value of options vested

	Three months ended March 31,
(in thousands, except per share amounts)	2014		2013
Weighted average fair value at grant date per share	$	N/A	$	25.22
Intrinsic value of options exercised	2,690		918
Fair value of options vested	391		838

Summary of the activity of the entity's stock options

	Number of options		Weighted average exercise price		Weighted average contractual term (in years)	Aggregate intrinsic value (in thousands)
Outstanding at December 31, 2013	2,589,343		$	18.33	5.20	$	363,293
Exercised	(28,538	)	14.25
Forfeited	(13,751	)	81.65
Outstanding at March 31, 2014	2,547,054		18.03		4.93	264,079
Exercisable at March 31, 2014	2,190,311		13.03		4.57	237,933