EQUITY - Narrative (Details) - USD ($)			12 Months Ended
	Jun. 30, 2015	Mar. 21, 2013	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Equity [Abstract]
Preferred stock, shares issued (in shares)		5,800,000	5,750,000	5,750,000
Preferred stock, dividend rate, percentage		7.125%
Redemption price per share (in dollars per share)		$ 25.00
Preferred stock, net proceeds from offering		$ 138,300,000
Preferred stock, dividends in arrears			$ 0
Convertible preferred stock, conversion price (in dollars per share)		$ 25.00
Convertible preferred stock, shares issued upon conversion (in shares)		1.7864
Common stock issuance (in shares)	5,900,000
Common stock, net proceeds from offering	$ 147,900,000		(1,289,000)	$ 139,403,000	$ 510,147,000
Price per share (in dollars per share)	$ 25.06
Tax withholding obligations			$ 1,500,000	$ 5,000,000