v2.4.0.6
STOCK-BASED COMPENSATION (Details 5) (USD $)
12 Months Ended
Dec. 31, 2012
Shares  
Nonvested at the beginning of the period (in shares) 798,710
Granted (in shares) 409,351
Vested (in shares) (487,515)
Forfeited and expired (in shares) (24,455)
Nonvested at the end of the period (in shares) 696,091
Weighted Average Grant Date Fair Value  
Nonvested at the beginning of the period (in dollars per share) $ 16.81
Granted (in dollars per share) $ 30.18
Vested (in dollars per share) $ 11.76
Forfeited and expired (in dollars per share) $ 25.86
Nonvested at the end of the period (in dollars per share) $ 27.90