Discontinued Operations - Income Statement (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Income (loss) from discontinued operations, net of income taxes	$ (30)	$ 0	$ 224	$ 3,501	$ (30,613)	$ 4,005	$ 4,636	$ 2,855	$ 3,695	$ (19,117)	$ (123,937)
Cole Capital [Member] | Held-for-sale or 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									1,027	16,096	36,526
Transaction service fees and reimbursements									334	13,929	12,533
Management fees and reimbursements									6,452	76,214	68,686
Total revenues									7,813	106,239	117,745
Cole Capital reallowed fees and commissions									602	9,879	23,174
Transaction costs									(654)	3,802	0
General and administrative									4,450	63,783	82,558
Amortization of intangible assets									0	14,490	26,148
Goodwill and intangible asset impairments									0	0	120,931
Total operating expenses									4,398	91,954	252,811
Other income, net									0	464	292
Loss on disposition and assets held for sale									(1,815)	(20,027)	0
Income (loss) before taxes									1,600	(5,278)	(134,774)
Benefit from (provision for) income taxes									2,095	(13,839)	10,837
Income (loss) from discontinued operations, net of income taxes									$ 3,695	$ (19,117)	$ (123,937)