CONSOLIDATED STATEMENTS OF CASH FLOWS $ in Thousands	12 Months Ended
	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)
Net loss	$ (126,503)	$ (32,848)	$ (12,713)
Depreciation	121,644	119,441	125,426
Amortization	14,554	12,057	3,981
Straight-line rent adjustments	1,989	2,686	2,602
Provision for doubtful accounts	2,461	1,763	1,357
Lease Termination Revenue Non Cash	(4,200)
Insurance Recoveries	(689)
Amortization of deferred compensation	6,925	5,709	6,035
Loss on hedge ineffectiveness	0	0	143
Gain on sales of interests in real estate and non-operating real estate, net	(9,625)	(909)	(23,402)
Equity in income of partnerships	(11,375)	(14,367)	(18,477)
Equity Method Investment, Realized Gain (Loss) on Disposal	(2,772)	(6,539)	0
Proceeds from Equity Method Investment, Distribution	9,421	16,849	22,094
Amortization of historic tax credits	829	1,768	1,768
Impairment of real estate assets	129,365	55,793	62,603
Impairment of mortgage note receivable	8,122
Net change in other assets	5,998	5,652	(4,566)
Net change in other liabilities	6,352	(4,752)	(12,312)
Net cash provided by operating activities	134,864	142,091	154,931
Payments to Acquire Commercial Real Estate	17,611	0	0
Cash proceeds from sales of real estate	13,730	77,778	154,758
Proceeds from Insurance Settlement, Investing Activities	700
Proceeds from Sale of Equity Method Investments	19,727	30,265
Proceeds from (Payments for) Other Financing Activities	123,000	35,221
Additions to construction in progress	75,649	116,550	88,161
Investments in real estate improvements	35,170	51,949	49,942
Additions to leasehold improvements and corporate fixed assets	160	683	522
Investments in equity method investees	58,112	73,434	14,910
Capitalized leasing costs	12,022	6,066	6,101
Net cash used in investing activities	(41,567)	(105,418)	(4,878)
Proceeds from Issuance of Preferred Stock and Preference Stock	0	286,847
Repayments under revolving facilities	(12,000)	(56,000)	(82,000)
Proceeds from mortgage loans	10,185	0	139,000
Repayment of mortgage loans	0	150,000	280,327
Principal installments on mortgage loans	18,655	17,945	17,868
Payment of deferred financing costs	5,529	71	3,337
Value of shares of beneficial interest issued	1,410	2,085	1,288
Dividends paid to common shareholders	59,145	58,651	58,372
Dividends paid to preferred shareholders	27,375	27,403	15,848
Distributions paid to Operating Partnership unit holders and noncontrolling interest	6,949	6,970	6,991
Value of shares retired under equity incentive plans, net of shares issued	747	1,477	2,177
Redeemable Noncontrolling Interest, Equity, Preferred, Redemption Value	0	(115,000)
Net cash used in financing activities	(94,805)	(32,585)	(162,632)
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Including Exchange Rate Effect	(1,508)	4,088	(12,579)
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Including Exchange Rate Effect	(1,508)	4,088	(12,579)
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents	$ 32,445	$ 33,953	$ 29,865