SHAREHOLDERS' EQUITY AND PARTNERS' CAPITAL (Allocations of Dividends and Declared and Paid For Income Tax Purposes) (Details) - USD ($) $ / shares in Units, $ in Thousands					12 Months Ended
	Jan. 16, 2017	Oct. 14, 2016	Jul. 15, 2016	Apr. 15, 2016	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Shareholders Equity [Line Items]
Common stock cash dividends per share (in dollars per share)		$ 0.265	$ 0.265	$ 0.265
Dividends payable					$ 45,259	$ 45,179
Common Stock
Shareholders Equity [Line Items]
Dividends declared (in usd per share)					$ 0.88	$ 1.06	$ 1.00
Allocations (percent)					100.00%	100.00%	100.00%
Common Stock | Ordinary income
Shareholders Equity [Line Items]
Allocations (percent)					100.00%	100.00%	100.00%
Common Stock | Capital gains 25% rate
Shareholders Equity [Line Items]
Allocations (percent)					0.00%	0.00%	0.00%
Common Stock | Return of capital
Shareholders Equity [Line Items]
Allocations (percent)					0.00%	0.00%	0.00%
Series D preferred stock
Shareholders Equity [Line Items]
Dividends declared (in usd per share)					$ 18.44	$ 18.44	$ 18.44
Series E preferred stock
Shareholders Equity [Line Items]
Dividends declared (in usd per share)					$ 16.56	$ 16.56	$ 16.56
Preferred Stock
Shareholders Equity [Line Items]
Allocations (percent)					100.00%	100.00%	100.00%
Preferred Stock | Ordinary income
Shareholders Equity [Line Items]
Allocations (percent)					100.00%	100.00%	100.00%
Preferred Stock | Capital gains 25% rate
Shareholders Equity [Line Items]
Allocations (percent)					0.00%	0.00%	0.00%
Subsequent Event
Shareholders Equity [Line Items]
Common stock cash dividends per share (in dollars per share)	$ 0.265
Tax Year 2016 | Subsequent Event
Shareholders Equity [Line Items]
Common stock cash dividends per share (in dollars per share)	0.081
Tax Year 2017 | Subsequent Event
Shareholders Equity [Line Items]
Common stock cash dividends per share (in dollars per share)	$ 0.184