SHARE-BASED PAYMENTS - Schedule of Stock Options Outstanding (Details) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2017 USD ($) $ / shares shares
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Beginning balance (in shares) | shares	124,640
Exercised (in shares) | shares	(124,640)
Ending balance (in shares) | shares	0
Weighted Average Exercise Price
Beginning balance (in dollars per share) | $ / shares	$ 25.84
Exercised (in dollars per share) | $ / shares	25.84
Ending balance (in dollars per share) | $ / shares	$ 0.00
Intrinsic Value (Millions)
Beginning balance | $	$ 3.7
Exercised | $	4.4
Ending balance | $	$ 0.0