Consolidated Statements Of Cash Flows $ in Thousands	12 Months Ended
	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)
Restricted Cash and Cash Equivalents	$ 12,635	$ 17,069	$ 9,744
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents	18,507	58,986	29,079
Operating activities:
Net income	266,983	262,968	224,982
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Gain on Extinguishment of Debt	0	(977)	0
Impairment charges	27,283	10,195	0
Gain on sale of real estate	(3,037)	(41,942)	(5,315)
Gain on insurance recovery	0	(606)	(4,684)
Deferred income tax benefit (expense)	573	812	(1,065)
Non-cash fee income	0	0	(1,588)
gain on sale of investment in direct financing lease	5,514	0	0
Costs associated with loan refinancing or payoff	31,958	1,549	905
Equity in loss (income) from joint ventures	22	(72)	(619)
Distributions from joint ventures	567	442	816
Depreciation and amortization	153,430	132,946	107,573
Amortization of deferred financing costs	5,797	6,167	4,787
Amortization of above/below-market leases and tenant allowances, net	(581)	(107)	183
Share-based compensation expense to management and trustees	15,111	14,142	11,164
Share-based compensation expense included in severance expense	3,218	0	0
(Increase) decrease in mortgage notes accrued interest receivable	(517)	467	572
(Increase) decrease in accounts receivable, net	(22,300)	8,866	(37,627)
Increase in direct financing lease receivable	(563)	(1,208)	(3,255)
Increase in other assets	(1,055)	(1,691)	(3,320)
Increase in accounts payable and accrued liabilities	4,979	260	17,025
Increase (decrease) in unearned rents and interest	7,974	6,061	(5,172)
Net cash provided by operating activities	484,328	398,272	305,362
Investing activities:
Acquisition of rental properties and other assets	(187,460)	(397,556)	(219,169)
Proceeds from Sale of Real Estate	22,134	191,569	23,860
Investment in unconsolidated joint ventures	29,473	0	0
Proceeds from settlement of derivative	(30,796)	0	0
Investment in mortgage notes receivable	(36,105)	(133,697)	(192,539)
Proceeds from mortgage note receivable paydown	335,168	21,784	72,072
Investment in promissory notes receivable	7,863	1,928	1,546
Proceeds from promissory note receivable paydown	7,500	1,599	0
Proceeds from sale of infrastructure related to issuance of revenue bonds	0	0	43,462
Proceeds from insurance recovery	0	606	4,610
Proceeds from Sale of Lease Receivables	43,447	0	20,951
Additions to properties under development	(274,956)	(384,449)	(413,848)
Net cash used by investing activities	(96,812)	(702,072)	(662,147)
Financing activities:
Proceeds from long-term debt facilities	908,000	1,371,000	1,380,000
Principal payments on long-term debt	(949,684)	(823,288)	(865,266)
Deferred financing fees paid	(8,642)	(14,318)	(14,385)
Costs associated with loan refinancing or payoff (cash portion)	(28,650)	(7)	(482)
Net proceeds from issuance of common shares	956	99,069	142,628
Proceeds from Issuance of Preferred Stock and Preference Stock	0	144,490	0
Payments for Repurchase of Redeemable Preferred Stock	0	125,025	0
Impact of stock option exercises, net	(62)	(5)	(1,488)
Purchase of common shares for treasury	(7,156)	(6,729)	(4,211)
Dividends paid to shareholders	(342,315)	(311,721)	(265,662)
Net cash (used) provided by financing activities	(427,553)	333,466	371,134
Effect of exchange rate changes on cash	(442)	241	(131)
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Including Exchange Rate Effect	(40,479)	29,907	14,218
Cash and cash equivalents at beginning of the year	41,917	19,335	4,283
Cash and cash equivalents at end of the year	5,872	41,917	19,335
Supplemental schedule of non-cash activity:
Transfer of property under development to rental property	228,572	408,593	454,922
Issuance of nonvested shares and restricted share units at fair value, including nonvested shares issued for payment of bonuses	18,252	24,062	19,626
Conversion of mortgage note receivable to rental property	155,185	9,237	0
Conversion of rental property to mortgage note receivable	0	11,897	0
Stock Issued During Period, Value, Acquisitions	0	657,473	0
Assumption of liabilities net of accounts receivable for acquisition	0	12,083	0
Transfer of investment in a direct financing lease to rental properties	0	35,807	0
Sale of investment in direct financing leases, net in exchange for mortgage note receivable	0	0	70,304
Supplemental disclosure of cash flow information:
Cash paid during the year for interest	145,559	136,345	96,410
Cash paid during the year for income taxes	1,363	1,499	1,684
Interest cost capitalized	9,903	9,879	10,697
Increase in accrued capital expenditures	$ 32,993	$ 333	$ 6,035