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SHARE-BASED COMPENSATION (Stock Option Activity) (Details) - Stock Options - USD ($)
$ / shares in Units, shares in Thousands, $ in Thousands
3 Months Ended
Mar. 31, 2018
Mar. 31, 2017
Share-based Compensation    
Total unrecognized compensation cost related to nonvested share-based compensation $ 2,600  
Total unrecognized compensation cost, recognized over a weighted-average period 2 years 10 months 6 days  
Intrinsic value of options exercised $ 400 $ 600
Stock Option Plans Activity and Related Information, Shares    
Outstanding beginning of period, shares 1,388  
Granted, shares 239  
Exercised, shares (25)  
Forfeited, shares (2)  
Outstanding end of period, shares 1,600  
Expected to vest after applying forfeiture rate, shares 1,569  
Vested and exercisable end of period, shares 1,064  
Stock Option Plans Activity and Related Information, Weighted Average Exercise Price    
Outstanding beginning of period, weighted-average exercise price $ 28.79  
Granted, weighted-average exercise price 40.25  
Exercised, weighted-average exercise price 25.68  
Forfeited, weighted-average exercise price 38.67  
Outstanding end of period, weighted-average exercise price 30.54  
Expected to vest after applying forfeiture rate, weighted-average exercise price 30.37  
Vested and exercisable end of period, weighted-average exercise price $ 26.73  
Summary of Weighted Average Remaining Contractual Term and Aggregate Intrinsic Value    
Outstanding at end of period, weighted-average remaining contractual term 5 years 11 months 4 days  
Outstanding at end of period, aggregate intrinsic value $ 16,890  
Expected to vest after applying forfeiture rate, weighted-average remaining contractual term 5 years 10 months 9 days  
Expected to vest after applying forfeiture rate, aggregate intrinsic value $ 16,823  
Vested and exercisable end of period, weighted-average remaining contractual term 4 years 4 months 27 days  
Vested and exercisable end of period, aggregate intrinsic value $ 15,232