STOCK-BASED COMPENSATION (Details - Stock Options Rollforward) (USD $)
3 Months Ended
Mar. 31, 2015
STOCK-BASED COMPENSATION  
Share Price $ 56.01
Stock options, Grant Date Fair Value Valuation  
Grant date fair value $ 20.78
Aggregate stock options  
Stock options, Shares  
Outstanding at the beginning of the period (in shares) 2,136,679
Granted (in shares) 11,478
Exercised (in shares) (898)
Forfeited (in shares) 0
Expired (in shares) (611)
Outstanding at the end of the period (in shares) 2,146,648
Options exercisable at the end of the period (in shares) 1,045,843
Stock options, Weighted Average Exercise Price  
Outstanding at the beginning of the period (in dollars per share) $ 18.16
Granted (in dollars per share) $ 53.24
Exercised (in dollars per share) $ 8.62
Forfeited (in dollars per share) $ 0.00
Expired (in dollars per share) $ 7.32
Outstanding at the end of the period (in dollars per share) $ 18.35
Options exercisable at the end of the period (in dollars per share) $ 9.33
Stock options, Weighted Average Remaining Contractual Term  
Outstanding at the end of the period 6 years 2 months 15 days
Options exercisable at the end of the period 3 years 7 months 17 days
Stock options, Aggregate Intrinsic Value  
Outstanding at the end of the period $ 80,839,000
Options exercisable at the end of the period 48,819,000
Stock options, Grant Date Fair Value Valuation  
Expected dividends $ 0
Expected dividend rate 0.00%
Expected volatility, minimum 38.00%
Expected volatility, maximum 38.00%
Risk-free interest rate, minimum 1.66%
Risk-free interest rate, maximum 1.74%
Stock options  
Stock options, Grant Date Fair Value Valuation  
Vesting period 3 years
Minimum | Aggregate stock options  
Stock options, Grant Date Fair Value Valuation  
Expected term P6Y0M
Minimum | Stock options  
Stock options, Grant Date Fair Value Valuation  
Grant date fair value   
Maximum | Aggregate stock options  
Stock options, Grant Date Fair Value Valuation  
Expected term P6Y0M
Maximum | Stock options  
Stock options, Grant Date Fair Value Valuation  
Grant date fair value