EQUITY - Common Stock and Preferred Stock (Details)			12 Months Ended
	Oct. 28, 2016 USD ($) $ / shares shares	Jun. 28, 2016 USD ($) shares	Dec. 31, 2016 USD ($) Vote $ / shares shares	Dec. 31, 2015 $ / shares shares	Aug. 02, 2016 USD ($)
Equity
Common stock, shares authorized			500,000,000	500,000,000
Common stock, par value (in dollars per share) | $ / shares			$ 0.01	$ 0.01
Number of votes a share of outstanding common stock is entitled | Vote			1
Restricted stock, shares withheld to cover employee tax obligations			61,622	36,385
Shares reserved for issuance			6,332,307	14,691,018
Preferred stock, shares authorized			100,000,000	100,000,000
Preferred stock, par value (in dollars per share) | $ / shares			$ 0.01	$ 0.01
Common stock issued (in shares)			6,151,514	0
Undesignated preferred stock
Equity
Preferred stock, shares authorized			88,600,000
9.25% Series A Preferred Stock
Equity
Preferred stock, shares authorized			2,000,000
Preferred stock, dividend rate (as a percent)			9.25%	9.25%
Payments to redeem outstanding preferred stock | $	$ 50,700,000
Preferred stock, shares outstanding	2,000,000			2,000,000
Preferred stock, redemption price per share | $ / shares	$ 25		$ 25
7.875% Series B Preferred Stock
Equity
Preferred stock, shares authorized			3,000,000
Preferred stock, dividend rate (as a percent)			7.875%	7.875%
Preferred stock, shares outstanding			3,000,000	3,000,000
Preferred stock, redemption price per share | $ / shares			$ 25
Annual dividend rate per share (in dollars per share) | $ / shares			$ 1.96875
7.875% Series B Preferred Stock | Maximum
Equity
Ratio for conversion			5.6497
7.125% Series C Preferred Stock
Equity
Preferred stock, shares authorized			3,400,000
Preferred stock, dividend rate (as a percent)			7.125%	7.125%
Preferred stock, shares outstanding			3,400,000	3,400,000
Preferred stock, redemption price per share | $ / shares			$ 25
Annual dividend rate per share (in dollars per share) | $ / shares			$ 1.78125
7.125% Series C Preferred Stock | Maximum
Equity
Ratio for conversion			5.1440
6.45% Series D Preferred Stock
Equity
Preferred stock, shares authorized			3,000,000
Preferred stock, dividend rate (as a percent)			6.45%
Common stock issued (in shares)		3,000,000
Net proceeds from sale of stock | $		$ 72,300,000
Underwriting discount and offering-related expenses | $		$ 2,700,000
Preferred stock, shares outstanding			3,000,000
Preferred stock, redemption price per share | $ / shares			$ 25
Annual dividend rate per share (in dollars per share) | $ / shares			$ 1.6125
6.45% Series D Preferred Stock | Maximum
Equity
Ratio for conversion			3.9216
2016 ATM Program
Equity
Common stock, par value (in dollars per share) | $ / shares			$ 0.01
Common stock, shares authorized, amount (up to) | $					$ 125,000,000.0
Compensation entitled as percentage of gross proceeds of shares sold under sales agreements					2.00%
Common stock issued (in shares)			6,151,514
Net proceeds from sale of stock | $			$ 89,100,000
2016 ATM Program | 6.45% Series D Preferred Stock
Equity
Preferred stock, par value (in dollars per share) | $ / shares			$ 0.01
Preferred stock, dividend rate (as a percent)			6.45%