v2.4.0.6
STOCK-BASED COMPENSATION (Details) (USD $)
In Thousands, except Share data, unless otherwise specified
3 Months Ended
Mar. 31, 2012
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]  
Volatility 34.82%
Risk-free interest rate 1.38%
Expected term (years) 5.9
Dividend yield 0.00%
Time-based stock options [Abstract]  
Exercised (in shares) (81,425)
Restricted stock [Abstract]  
Weighted-average Black-Scholes fair value $ 15.09
Weighted-average exercise price $ 42.61
2012 $ 9,425
2013 10,920
2014 8,879
2015 4,818
Total 34,042
Employee Stock Option [Member]
 
Time-based stock options [Abstract]  
Outstanding, beginning balance (in shares) 1,992,700
Granted (in shares) 343,600
Exercised (in shares) 81,425
Forfeited (in shares) (1,800)
Expired (in shares) 0
Outstanding, ending balance (in shares) 2,253,075
Exercisable, end of period (in shares) 1,216,550
Restricted stock [Abstract]  
Stock-based compensation expense 129,000
2012 3,184
2013 3,588
2014 2,612
2015 1,448
Total 10,832
Restricted Stock [Member]
 
Restricted stock [Abstract]  
Outstanding, beginning balance (in shares) 617,401
Granted (in shares) 323,800
Vested restricted stock (in shares) (133,207)
Forfeited (in shares) (900)
Outstanding, ending balance (in shares) 807,094
Stock-based compensation expense 373,000
Restricted stock weighted-average fair value $ 42.61
2012 6,241
2013 7,332
2014 6,267
2015 3,370
Total $ 23,210
Performance-based Restricted Stock Awards to the CEO [Member]
 
Restricted stock [Abstract]  
Granted (in shares) 100,000
Restricted stock weighted-average fair value $ 42.61
Performance-based Restricted Stock Awards [Member]
 
Restricted stock [Abstract]  
Granted (in shares) 52,000
Restricted stock weighted-average fair value $ 42.61