Annual report pursuant to Section 13 and 15(d)

STOCK-BASED COMPENSATION (Summary of stock-based compensation expense) (Details)

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STOCK-BASED COMPENSATION (Summary of stock-based compensation expense) (Details) - USD ($)
$ in Thousands
 12 Months Ended
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]      
Total stock-based compensation expense $ 42,755 $ 32,723 $ 33,361
Total unrecognized compensation cost $ 116,200    
Amortization period of unrecognized compensation cost 4 years 1 month    
Selling, general, and administrative expenses [Member]      
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]      
Total stock-based compensation expense $ 24,364 15,687 16,380
Corporate expenses [Member]      
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]      
Total stock-based compensation expense 18,391 $ 17,036 $ 16,981
Other Equity Award [Member] | Selling, general, and administrative expenses [Member]      
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]      
Total stock-based compensation expense $ 10,000