SHAREHOLDERS' EQUITY AND PARTNERS' CAPITAL (Details)	3 Months Ended	12 Months Ended
	Sep. 30, 2015 USD ($) shares	Dec. 31, 2016 USD ($) unitholder $ / shares shares	Dec. 31, 2015 $ / shares shares	Dec. 31, 2014 USD ($) unitholder shares
Common Stock [Abstract]
Stock repurchase program, authorized amount | $	$ 200,000
Shares repurchased in period | shares	0
Redemption of units, value | $		$ 11,754,000		$ 4,861,000
Number of holders of common units who received cash for their units | unitholder		4		4
Redeemable noncontrolling interest, units exercised for conversion (shares) | shares		964,796		272,952
Preferred Stock [Abstract]
Preferred stock, shares authorized (in shares) | shares		15,000,000
Preferred stock, par value (in dollars per share) | $ / shares		$ 0.01
Public offering, shares issued | shares		335,417	278,093	246,168
Operating Partnership
Common Stock [Abstract]
Common units outstanding | shares		199,085,032	199,748,131
Operating Partnership | Common Units
Common Stock [Abstract]
Noncontrolling interest conversion, calculation of trailing average of trading price, term (days)		5 days
Common Stock
Common Stock [Abstract]
Common stock, shares authorized (in shares) | shares		350,000,000
Common stock, par value (in dollars per share) | $ / shares		$ 0.01
Common stock, shares outstanding (in shares) | shares		170,792,645	170,490,948
Preferred Stock [Abstract]
Public offering, shares issued | shares		8,419,298
Series E preferred stock
Preferred Stock [Abstract]
Preferred stock, par value (in dollars per share) | $ / shares		$ 0.01	$ 0.01
Public offering, shares issued | shares		6,900,000	6,900,000
Preferred stock represented by one depository share (in shares) | shares		0.1	0.1
Dividend rate (in thousandths)		6.625%	6.625%
Preferred stock, liquidation preference per share | $ / shares		$ 250.00
Depositary shares, liquidation preference (in dollars per share) | $ / shares		25
Dividends in arrears per share (in dollars per share) | $ / shares		16.5625
Dividends in arrears per depositary share (in dollars per share) | $ / shares		1.65625
7.375% Series D Cumulative Redeemable Preferred Stock
Preferred Stock [Abstract]
Preferred stock, par value (in dollars per share) | $ / shares		$ 0.01	$ 0.01
Preferred stock represented by one depository share (in shares) | shares		0.1	0.1
Dividend rate (in thousandths)		7.375%	7.375%
Preferred stock, liquidation preference per share | $ / shares		$ 250
Depositary shares, liquidation preference (in dollars per share) | $ / shares		25
Dividends in arrears per share (in dollars per share) | $ / shares		18.4375
Dividends in arrears per depositary share (in dollars per share) | $ / shares		$ 1.84375
Depositary shares outstanding | shares		18,150,000	18,150,000