Rent and Tenant Receivables and Other Assets, Net (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018
Property, Plant and Equipment [Line Items]
Straight-line rent receivable, net	$ 261,074,000		$ 261,074,000		$ 259,106,000
Accounts receivable, net	38,732,000		38,732,000		36,939,000
Deferred costs, net	10,359,000		10,359,000		17,515,000
Investment in direct financing leases, net	9,914,000		9,914,000		13,254,000
Investment in Cole REITs	7,552,000		7,552,000		7,844,000
Prepaid expenses	6,662,000		6,662,000		5,022,000
Leasehold improvements, property and equipment, net	5,042,000		5,042,000		9,754,000
Other assets, net	8,120,000		8,120,000		16,658,000
Total	347,455,000		347,455,000		366,092,000
Write off of depreciation	0	$ 0		$ 0
Property and equipment disposed of	4,100,000		4,100,000
Leasehold Improvements [Member]
Property, Plant and Equipment [Line Items]
Amortization expense	100,000	300,000	600,000	900,000
Write off of leasehold	0	0	0	0
Accumulated amortization	2,700,000		2,700,000		5,900,000
Property and Equipment [Member]
Property, Plant and Equipment [Line Items]
Accumulated amortization	5,100,000		5,100,000		7,000,000.0
Depreciation expense	300,000	300,000	1,000,000.0	1,200,000
Line of Credit [Member]
Property, Plant and Equipment [Line Items]
Amortization expense	900,000	$ 1,300,000	2,900,000	$ 6,000,000.0
Accumulated amortization for deferred costs	$ 50,600,000		50,600,000		47,600,000
Rent Receivables [Member]
Property, Plant and Equipment [Line Items]
Allowance for doubtful accounts					1,000,000.0
Accounts Receivable [Member]
Property, Plant and Equipment [Line Items]
Allowance for doubtful accounts					$ 5,300,000
Maximum [Member]
Property, Plant and Equipment [Line Items]
Write off of depreciation			$ 100,000