CAPITAL STOCK AND SHARE-BASED COMPENSATION - Employee Stock Purchase Plan Purchases (Details) - $ / shares	3 Months Ended								43 Months Ended	67 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Dec. 31, 2017
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Employee Stock Purchase Plan shares issued (shares)	13,323	12,276	11,446	13,244	16,882	16,520	14,236	13,850	2,977,712	3,089,489
Price per Employee Stock Purchase Plan share issued (usd per share)	$ 44.80	$ 47.57	$ 53.39	$ 43.43	$ 36.24	$ 40.32	$ 42.91	$ 41.09	$ 14.20	$ 44.80