COMMON STOCK REPURCHASE PROGRAM (Details)	12 Months Ended
	Dec. 31, 2018 $ / shares shares
COMMON SHARE REPURCHASE PROGRAM
Shares authorized for repurchase under share repurchase program (in shares)	55,000,000
Shares purchased in the open market under share repurchase program (in shares)	2,251,350
Average cost per share of shares purchased in the open market under share repurchase program (in dollars per share) | $ / shares	$ 88.84
Remaining shares available for repurchase under the stock repurchase program (in shares)	6,177,224