RELATED PARTY TRANSACTIONS - Additional Information (Details) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Dec. 31, 2016
Related Party Transaction [Line Items]
Reimbursement Agreements termination notice period	90 days
Insurance program renewal period	5 years
Reimbursement Agreements
Related Party Transaction [Line Items]
Expenses related party	$ 4.0	$ 1.4
Payable to related party	0.1		$ 0.2
Majority Shareholder | Related party expense, coupon redemptions
Related Party Transaction [Line Items]
Expenses related party	18.5	24.8
Majority Shareholder | Related party expense, coupon redemption processing
Related Party Transaction [Line Items]
Expenses related party	0.2	0.2
Majority Shareholder | Related party expense, other fees
Related Party Transaction [Line Items]
Expenses related party	$ 0.2	$ 0.2