SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Debt Issuance Costs (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018
Accounting Policies [Abstract]
Deferred debt issuance cost			$ 0.8
Unamortized debt issuance expense	$ 4.0	$ 4.0		$ 3.5
Amortization of debt issuance costs	$ 0.2	$ 0.4
Unamortized debt issuance cost amortization period		4 years 7 months 6 days