LONG-TERM INCENTIVE COMPENSATION (Details 1) - Restricted Shares Subject Only to a Service Condition	9 Months Ended
	Sep. 30, 2018 $ / shares shares
Restricted shares subject only to a service condition:
Non-vested, beginning balance, shares | shares	519,375
Granted (shares) | shares	172,366
Vested (shares) | shares	(203,504)
Forfeited (shares) | shares	(29,229)
Non-vested, ending balance, shares | shares	459,008
Non-vested, beginning balance, (dollars per share) | $ / shares	$ 55.44
Granted (dollars per share) | $ / shares	55.92
Vested (dollars per share) | $ / shares	53.49
Forfeited (dollars per share) | $ / shares	56.55
Non-vested, ending balance, (dollars per share) | $ / shares	$ 56.42