Consolidated Statements Of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Operating activities:
Net income	$ 65,349	$ 29,538
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Gain on sale of real estate	(6,328)	0
Deferred income tax (benefit) expense	(609)	428
Costs associated with loan refinancing or payoff	0	31,943
Equity in income from joint ventures	489	51
Proceeds from Equity Method Investment, Distribution	112	116
Depreciation and amortization	39,743	37,684
Amortization of deferred financing costs	1,502	1,398
Amortization of above/below market leases and tenant allowances, net	(59)	(417)
Share-based compensation expense to management and trustees	3,280	3,791
Right-of-Use Asset Obtained in Exchange for Operating Lease Liability	445	0
(Increase) decrease in mortgage notes accrued interest receivable	(135)	845
Decrease in accounts receivable	14,669	3,597
Increase in direct financing lease receivable	(58)	(198)
Increase in other assets	(5,673)	(3,826)
Increase (decrease) in accounts payable and accrued liabilities	4,684	(9,118)
Increase in unearned rents and interest	5,951	13,234
Net cash provided by operating activities	122,384	108,964
Investing activities:
Acquisition of and investments in rental properties and other assets	93,322	38,869
Proceeds from sale of real estate	37,810	0
Investment in unconsolidated joint ventures	325	0
Investment in mortgage notes receivable	(10,998)	(16,223)
Proceeds from mortgage note receivable paydown	973	11,555
Investment in promissory notes receivable	61	7,677
Additions to properties under development	(61,910)	(55,702)
Net cash used by investing activities	(127,833)	(106,916)
Financing activities:
Proceeds from long-term debt facilities	100,000	380,000
Principal payments on long-term debt	(66,150)	(281,684)
Deferred financing fees paid	(40)	(38)
Costs associated with loan refinancing or payoff (cash portion)	0	(28,650)
Net proceeds from issuance of common shares	74,323	303
Impact of stock option exercises, net	(732)	0
Purchase of common shares for treasury	(9,499)	(7,116)
Dividends paid to shareholders	(88,748)	(83,613)
Net cash provided (used) by financing activities	9,154	(20,798)
Effect of exchange rate changes on cash	70	(82)
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Including Exchange Rate Effect	3,775	(18,832)
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents	22,282	40,154
Cash and Cash Equivalents, at Carrying Value	11,116	24,514
Restricted Cash and Cash Equivalents	11,166	15,640
Supplemental schedule of non-cash activity:
Transfer of property under development to rental property	7,330	55,377
Issuance of nonvested shares and restricted share units at fair value, including nonvested shares issued for payment of bonuses	14,682	16,809
Noncash or Part Noncash Acquisition, Value of Assets Acquired	0	155,185
Operating Lease, Cost		0
Straight-Line Rent Receivable	98,372
Other Real Estate, Additions	14,000	0
Noncash or Part Noncash Acquisition, Debt Assumed	18,585	0
Supplemental disclosure of cash flow information:
Cash paid during the year for interest	28,676	41,948
Cash paid during the period for income taxes	695	290
Interest cost capitalized	3,137	2,244
Decrease in accrued capital expenditures	(6,406)	(4,278)
Ground Lease Arrangement [Member]
Supplemental schedule of non-cash activity:
Straight-Line Rent Receivable	$ 24,638	$ 0