Rental Properties Disposition (Details)			12 Months Ended
	Apr. 06, 2017 USD ($)	May 22, 2015 properties	Dec. 31, 2017 USD ($) properties	Dec. 31, 2016 USD ($) properties	Dec. 31, 2015 USD ($)
Significant Acquisitions and Disposals [Line Items]
Payments to Acquire Property, Plant, and Equipment	$ 61,200,000
Gain on sale of real estate			$ 41,942,000	$ 5,315,000	$ 23,829,000
number of properties sold | properties		1	9
Entertainment Reportable Operating Segment [Member]
Significant Acquisitions and Disposals [Line Items]
number of properties sold			4
Proceeds from Sale of Property, Plant, and Equipment			$ 72,400,000
Gain (Loss) on Disposition of Assets			19,400,000
Education Property [Member]
Significant Acquisitions and Disposals [Line Items]
Payments to Acquire Property, Plant, and Equipment			$ 38,500,000	16,500,000
Gain on sale of real estate				$ 2,800,000
number of properties sold			3	2
Proceeds from Sale of Property, Plant, and Equipment				$ 16,600,000
number of properties sold pursuant to tenant purchase option			8
Education Property [Member] | Education Reportable Operating Segment [Member]
Significant Acquisitions and Disposals [Line Items]
Proceeds from Sale of Property, Plant, and Equipment			$ 10,500,000
Gain (Loss) on Disposition of Assets			1,800,000
Proceeds from sale of property, plant, and equipment tenant purchase option			97,300,000
Gain (Loss) on disposition of assets from tenant purchase option			$ 20,700,000
Retail Site [Member]
Significant Acquisitions and Disposals [Line Items]
Gain on sale of real estate				$ 2,500,000
number of properties sold | properties				3
Proceeds from Sale of Property, Plant, and Equipment				$ 5,300,000
Theatre Properties Member
Significant Acquisitions and Disposals [Line Items]
Number of properties acquired			6	8
Payments to Acquire Property, Plant, and Equipment			$ 154,100,000	$ 148,400,000
Other Recreation [Member]
Significant Acquisitions and Disposals [Line Items]
Number of properties acquired			6
Payments to Acquire Property, Plant, and Equipment			$ 62,700,000
early childhood education center [Member]
Significant Acquisitions and Disposals [Line Items]
Number of properties acquired			7	4
Public charter school properties [Member]
Significant Acquisitions and Disposals [Line Items]
Number of properties acquired			2
private school [Member]
Significant Acquisitions and Disposals [Line Items]
Number of properties acquired				1
Land [Member]
Significant Acquisitions and Disposals [Line Items]
Gain on sale of real estate				$ 0
Proceeds from Sale of Property, Plant, and Equipment				$ 1,500,000