| STOCK OPTION AND PURCHASE PLANS (Tables)
 | 12 Months Ended | 
      
        | Dec. 31, 2013 | 
      
        | Disclosure Of Compensation Related Costs Sharebased Payments [Abstract] |  | 
      
        | Summary of Weighted Average Fair Value of Options Granted | 
 
  In general,
 options granted to outside directors vest six months from the date
 of grant and options granted to officers and key employees straight
 line vest over a five-year period from the date of grant. 
   
 
 |  |  |  |  |  |  |  |  |  |  |  |  |  |  
 |  |  | 2013 |  |  | 2012 |  |  | 2011 |  |  
 | 
 Weighted Average Fair Value of the Options Granted |  | $ | 23.22 |  |  | $ | 9.93 |  |  | $ | 12.65 |  |  | 
      
        | Summary of Weighted-Average Assumptions | 
 
 The weighted average fair value for these options was estimated at
 the date of grant using a Black-Scholes option pricing model with
 the following weighted-average assumptions: 
   
 
 |  |  |  |  |  |  |  |  
 |  |  | 2013 |  | 2012 |  | 2011 |  
 | 
 Risk-free Interest Rate |  | 0.88% - 2.22% |  | 0.89% - 1.00% |  | 1.55% - 2.82% |  
 | 
 Dividend Yield |  | 0.0% |  | 0.0% |  | 0.0% |  
 | 
 Volatility Factor |  | 0.51-0.56 |  | 0.52-0.64 |  | 0.52-0.53 |  
 | 
 Expected Life in Years |  | 5.0 – 8.0 |  | 5.0 – 8.0 |  | 7.0 – 8.0 |  | 
      
        | Compensation Expense Information Based on Fair Value of Stock Options | 
 
 The following table provides compensation expense information based
 on the fair value of stock options for the years ended
 December 31, 2013, 2012 and 2011: 
   
 
 |  |  |  |  |  |  |  |  |  |  |  |  |  |  
 | (In thousands) |  | 2013 |  |  | 2012 |  |  | 2011 |  |  
 | 
 Stock Compensation Expense |  | $ | 1,384 |  |  | $ | 1,351 |  |  | $ | 1,061 |  |  
 | 
 Tax Benefit |  |  | (112 | ) |  |  | (136 | ) |  |  | (93 | ) |  
 |  |  |   |   |  |  |   |   |  |  |   |   |  |  
 | 
 Stock Compensation Expense, Net of Tax |  | $ | 1,272 |  |  | $ | 1,215 |  |  | $ | 968 |  |  
 |  |  |   |   |  |  |   |   |  |  |   |   |  |  | 
      
        | Summary of Company's Stock Option Activity and Related Information | 
 
 A summary of the Company’s stock option activity and related
 information for the years ended December 31 is as follows: 
   
 
 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  
 | (Aggregate intrinsic value in thousands) |  | 2013 |  |  | 2012 |  |  | 2011 |  |  
 |  |  | Options |  |  | Weighted Average
 Exercise
 Price
 |  |  | Aggregate Intrinsic
 Value
 |  |  | Options |  |  | Weighted Average
 Exercise
 Price
 |  |  | Aggregate Intrinsic
 Value
 |  |  | Options |  |  | Weighted Average
 Exercise
 Price
 |  |  | Aggregate Intrinsic
 Value
 |  |  
 |  |  |  |  |  |  |  |  |  |  |  
 | 
 Outstanding at January 1 |  |  | 1,521,275 |  |  | $ | 8.23 |  |  | $ | 65,072 |  |  |  | 1,661,445 |  |  | $ | 6.71 |  |  | $ | 20,532 |  |  |  | 1,904,232 |  |  | $ | 5.58 |  |  | $ | 38,778 |  |  
 |  |  |  |  |  |  |  |  |  |  |  
 | 
 Options Granted |  |  | 69,720 |  |  | $ | 42.67 |  |  | $ | 581 |  |  |  | 130,500 |  |  | $ | 18.08 |  |  | $ | 129 |  |  |  | 84,938 |  |  | $ | 22.44 |  |  | $ | 299 |  |  
 |  |  |  |  |  |  |  |  |  |  |  
 | 
 Options Exercised |  |  | (181,218 | ) |  | $ | 4.25 |  |  | $ | (8,472 | ) |  |  | (270,670 | ) |  | $ | 3.67 |  |  | $ | (4,168 | ) |  |  | (327,725 | ) |  | $ | 4.25 |  |  | $ | (7,112 | ) |  
 |  |  |  |  |  |  |  |  |  |  |  
 | 
 Options Forfeited |  |  | — |  |  | $ | — |  |  | $ | — |  |  |  | — |  |  | $ | — |  |  | $ | — |  |  |  | — |  |  | $ | — |  |  | $ | — |  |  
 |  |  |  |  |  |  |  |  |  |  |  
 | 
 Outstanding at December 31 |  |  | 1,409,777 |  |  | $ | 10.44 |  |  | $ | 57,181 |  |  |  | 1,521,275 |  |  | $ | 8.23 |  |  | $ | 16,493 |  |  |  | 1,661,445 |  |  | $ | 6.71 |  |  | $ | 31,965 |  |  
 |  |  |  |  |  |  |  |  |  |  |  
 | 
 Exercisable at December 31 |  |  | 1,149,532 |  |  | $ | 7.81 |  |  | $ | 49,648 |  |  |  | 1,168,459 |  |  | $ | 6.72 |  |  | $ | 14,431 |  |  |  | 1,280,744 |  |  | $ | 5.47 |  |  | $ | 26,237 |  |  | 
      
        | Summary of Weighted Average Exercise Prices and Contractual Lives for Outstanding and Exercisable Stock Options | 
 
 The following is a summary of weighted average exercise prices and
 contractual lives for outstanding and exercisable stock options as
 of December 31, 2013: 
   
 
 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  
 |  |  | Outstanding |  |  | Exercisable |  |  
 | 
 Exercise Price Range |  | Shares |  |  | Weighted Average Remaining Life
 in Years
 |  |  | Weighted Average Exercise Price
 |  |  | Shares |  |  | Weighted Average Remaining Life
 in Years
 |  |  | Weighted Average
 Exercise Price
 |  |  
 |  |  |  |  |  |  |  |  
 | 
 $  2.68 - $ 3.45 |  |  | 265,404 |  |  |  | 0.9 |  |  | $ | 3.07 |  |  |  | 265,404 |  |  |  | 0.9 |  |  | $ | 3.07 |  |  
 | 
 $  4.84 - $ 7.07 |  |  | 578,364 |  |  |  | 4.7 |  |  |  | 5.34 |  |  |  | 533,109 |  |  |  | 4.6 |  |  |  | 5.35 |  |  
 | 
 $  9.15 - $10.07 |  |  | 141,975 |  |  |  | 3.2 |  |  |  | 9.35 |  |  |  | 141,975 |  |  |  | 3.2 |  |  |  | 9.35 |  |  
 | 
 $14.01 - $24.88 |  |  | 372,314 |  |  |  | 7.5 |  |  |  | 18.62 |  |  |  | 209,044 |  |  |  | 6.9 |  |  |  | 19.08 |  |  
 | 
 $41.40 - $51.93 |  |  | 51,720 |  |  |  | 9.9 |  |  |  | 49.49 |  |  |  | — |  |  |  | — |  |  |  | — |  |  
 |  |  |   |   |  |  |  |  |  |  |  |  |  |  |   |   |  |  |  |  |  |  |  |  |  |  
 |  |  |  | 1,409,777 |  |  |  | 4.8 |  |  |  | 10.44 |  |  |  | 1,149,532 |  |  |  | 4.0 |  |  |  | 7.81 |  |  
 |  |  |   |   |  |  |  |  |  |  |  |  |  |  |   |   |  |  |  |  |  |  |  |  |  | 
      
        | Fair Value for Options Granted under Employee Stock Purchase Plan | 
 
 The fair value for the options granted under the Employee Stock
 Purchase Plan was estimated at the date of grant using a
 Black-Scholes option pricing model with the following
 weighted-average assumptions: 
   
 
 |  |  |  |  |  |  |  |  |  |  |  |  |  |  
 |  |  | 2013 |  |  | 2012 |  |  | 2011 |  |  
 | 
 Risk-free Interest Rate |  |  | 0.10 | % |  |  | 0.17 | % |  |  | 0.10 | % |  
 | 
 Dividend Yield |  |  | 0.0 | % |  |  | 0.0 | % |  |  | 0.0 | % |  
 | 
 Volatility Factor |  |  | .37 |  |  |  | .37 |  |  |  | .52 |  |  
 | 
 Expected Life in Years |  |  | 1.0 |  |  |  | 1.0 |  |  |  | 1.0 |  |  |