STOCKHOLDERS' EQUITY, Restricted Stock and Performance Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016
Weighted Average Assumptions [Abstract]
Unrecognized compensation cost related to non-vested shares	$ 10,754	$ 12,167
Weighted-average period of recognition for unrecognized compensation cost	1 year 6 months
Estimated share-based compensation expense for current fiscal year	$ 6,200
Restricted Stock [Member]
Non-vested restricted stock [Roll Forward]
Non-vested balance as of beginning of period (in shares)	102	150
Granted (in shares)	9	18
Vested (in shares)	(41)	(52)
Forfeited (in shares)	(4)	0
Non-vested balance as of end of period (in shares)	66	116
Weighted average grant date fair value [Abstract]
Non-vested balance as of beginning of period (in dollars per share)	$ 54.18	$ 47.46
Granted (in dollars per share)	85.40	60.85
Vested (in dollars per share)	50.07	42.36
Forfeited (in dollars per share)	55.45	0
Non-vested balance as of end of period (in dollars per share)	$ 61.05	$ 51.83
Performance Shares [Member]
Non-vested restricted stock [Roll Forward]
Non-vested balance as of beginning of period (in shares)	34	20
Granted (in shares)	16	21
Vested (in shares)	0	0
Forfeited (in shares)	(7)	(4)
Non-vested balance as of end of period (in shares)	43	37
Weighted average grant date fair value [Abstract]
Non-vested balance as of beginning of period (in dollars per share)	$ 61.06	$ 58.77
Granted (in dollars per share)	93.85	63.15
Vested (in dollars per share)	0	0
Forfeited (in dollars per share)	69.18	60.87
Non-vested balance as of end of period (in dollars per share)	$ 72.26	$ 61.04
Weighted Average Assumptions [Abstract]
Risk-free interest rate	1.50%	0.88%
Dividend yield	0.60%	0.60%
Expected volatility	32.00%	32.00%
Initial TSR	8.20%	(6.60%)
Vesting percentage at the end of the third year following the grant	100.00%