Rental Properties Summary Of Carrying Amounts Of Rental Properties (Details)	12 Months Ended
	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)
Real Estate Properties [Line Items]
Real Estate Investment Property, at Cost	$ 6,186,562,000	$ 5,907,231,000
Gain (Loss) on Disposition of Assets	4,174,000	3,037,000	$ 41,942,000
Accumulated depreciation	(989,254,000)	(883,174,000)
Total	5,197,308,000	5,024,057,000
Depreciation expense on rental properties	153,200,000	133,700,000	$ 117,600,000
Building and Building Improvements [Member]
Real Estate Properties [Line Items]
Real Estate Investment Property, at Cost	4,747,101,000	4,593,159,000
Adelaar Infrastructure [Member]
Real Estate Properties [Line Items]
Reimbursement received from payment of economic development revenue bonds	11,500,000	74,200,000
Special Assessment Bond	110,000,000.0
Furniture and Fixtures [Member]
Real Estate Properties [Line Items]
Real Estate Investment Property, at Cost	123,239,000	97,463,000
Land [Member]
Real Estate Properties [Line Items]
Real Estate Investment Property, at Cost	1,290,181,000	1,190,568,000
Leaseholds and Leasehold Improvements [Member]
Real Estate Properties [Line Items]
Real Estate Investment Property, at Cost	$ 26,041,000	$ 26,041,000
Theatre Properties Member
Real Estate Properties [Line Items]
Number of properties acquired	26	2
Payments to Acquire Property, Plant, and Equipment	$ 426,500,000	$ 22,400,000
Fitness & Wellness Properties [Member]
Real Estate Properties [Line Items]
Payments to Acquire Property, Plant, and Equipment		7,800,000
Eat & Play Properties [Member]
Real Estate Properties [Line Items]
Number of properties acquired	1
Payments to Acquire Property, Plant, and Equipment	$ 1,400,000
Cultural Properties [Member]
Real Estate Properties [Line Items]
Number of properties acquired	2
Payments to Acquire Property, Plant, and Equipment	$ 24,000,000.0	50,300,000
Experiential Lodging Properties [Member]
Real Estate Properties [Line Items]
Payments to Acquire Property, Plant, and Equipment		$ 36,600,000
early childhood education center [Member]
Real Estate Properties [Line Items]
number of properties sold	1	2
Proceeds from Sale of Property, Plant, and Equipment		$ 2,500,000
Gain (Loss) on Disposition of Assets		$ 0
Number of properties acquired	2	4
Payments to Acquire Property, Plant, and Equipment		$ 17,700,000
Experiential Reportable Operating Segment [Member]
Real Estate Properties [Line Items]
number of properties sold	4	4
Proceeds from Sale of Property, Plant, and Equipment	$ 21,900,000	$ 7,300,000
Gain (Loss) on Disposition of Assets	4,200,000	1,200,000
Investment Building and Building Improvements	146,200,000	288,100,000
Payments to Acquire Property, Plant, and Equipment	451,900,000
Education Reportable Operating Segment [Member]
Real Estate Properties [Line Items]
Investment Building and Building Improvements	38,600,000	$ 49,700,000
Payments to Acquire Property, Plant, and Equipment	$ 5,900,000