Discontinued Operations - Income Statement (Details) - USD ($) $ in Thousands	3 Months Ended			9 Months Ended
	Sep. 30, 2018	Dec. 31, 2017	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Income from discontinued operations	$ 0		$ 4,005	$ 3,725	$ 11,496
Loss on disposition		$ 20,000		1,800
Cole Capital [Member] | Held-for-sale of Disposed of by Sale [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Offering-related fees and reimbursements	0		3,882	1,027	12,721
Transaction service fees and reimbursements	0		3,964	334	12,110
Management fees and reimbursements	0		19,152	6,452	56,388
Total revenues	0		26,998	7,813	81,219
Cole Capital reallowed fees and commissions	0		2,373	602	7,907
Transaction costs	0		0	(654)	0
General and administrative	0		16,072	4,450	46,426
Amortization of intangible assets	0		4,140	0	12,420
Total operating expenses	0		22,585	4,398	66,753
Operating income	0		4,413	3,415	14,466
Other income, net	0		460	(1,785)	469
Income before taxes	0		4,873	1,630	14,935
Benefit from (provision for) income taxes	0		(868)	2,095	(3,439)
Income from discontinued operations	$ 0		$ 4,005	$ 3,725	$ 11,496