Rent and Tenant Receivables and Other Assets, Net (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019	Dec. 31, 2019
Property, Plant and Equipment [Line Items]
Straight-line rent receivable, net	$ 266,823,000		$ 266,823,000		$ 266,195,000
Accounts receivable, net	64,791,000		64,791,000		41,556,000
Mezzanine position	9,959,000		9,959,000		0
Deferred costs, net	6,927,000		6,927,000		7,208,000
Investment in direct financing leases, net	8,579,000		8,579,000		9,341,000
Investment in Cole REITs	6,867,000		6,867,000		7,552,000
Prepaid expenses	6,538,000		6,538,000		3,453,000
Leasehold improvements, property and equipment, net	4,317,000		4,317,000		4,809,000
Other assets, net	7,608,000		7,608,000		8,281,000
Total	382,409,000		382,409,000		348,395,000
Unrealized gain (loss) included in consolidated statement of operations			(700,000)
Write off of depreciation			0	$ 0
Leasehold Improvements [Member]
Property, Plant and Equipment [Line Items]
Amortization expense	100,000	$ 100,000	300,000	400,000
Write off of leasehold			0	0
Accumulated amortization	3,100,000		3,100,000		2,800,000
Property and Equipment [Member]
Property, Plant and Equipment [Line Items]
Accumulated amortization	6,000,000.0		6,000,000.0		5,400,000
Depreciation expense	300,000	300,000	600,000	700,000
Line of Credit [Member]
Property, Plant and Equipment [Line Items]
Amortization expense	800,000	$ 900,000	1,500,000	2,000,000.0
Accumulated amortization for deferred costs	$ 51,200,000		$ 51,200,000		$ 49,800,000
Maximum [Member]
Property, Plant and Equipment [Line Items]
Write off of depreciation				$ 100,000