EQUITY - Preferred Stock (Details) - USD ($) $ / shares in Units, $ in Millions			9 Months Ended
	Jun. 01, 2018	Mar. 21, 2013	Sep. 30, 2018	Dec. 31, 2017
Class of Stock [Line Items]
Shares of preferred stock issued (in shares)		5,750,000.00		5,750,000
Preferred stock dividend rate		7.125%
Price per share of preferred stock (in dollars per share)		$ 25.00
Net proceeds from preferred stock offering		$ 138.3
Redemption price (in dollars per share)	$ 25.00
Accrued and unpaid dividends (in dollars per share)	0.4453125
Total redemption price (in dollars per share)	$ 25.4453125
Redemption charge related to original issuance costs	$ 5.5
Preferred Stock
Class of Stock [Line Items]
Shares of preferred stock redeemed (in shares)	5,750,000		5,750,000