STOCK-BASED COMPENSATION PLANS - Summary of Stock Option Activity (Details)	12 Months Ended
	Dec. 31, 2017 $ / shares shares
Shares
Granted (in shares)	0
Stock options
Shares
Balance, December 31, 2016 (in shares)	795,000
Granted (in shares)	0
Exercised (in shares)	(49,000)
Forfeitures and post-vesting cancellations (in shares)	(430,000)
Balance, December 31, 2017 (in shares)	316,000
Exercisable, December 31, 2017 (in shares)	277,000
Weighted Average Exercise Price
Balance, December 31, 2016 (in dollars per share) | $ / shares	$ 27.80
Granted (in dollars per share) | $ / shares	0.00
Exercised (in dollars per share) | $ / shares	8.80
Forfeitures and post-vesting cancellations (in dollars per share) | $ / shares	31.72
Balance, December 31, 2017 (in dollars per share) | $ / shares	25.40
Exercisable, December 31, 2017 (in dollars per share) | $ / shares	$ 26.25