Related Party Transactions and Arrangements - Schedule of Revenue (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Jan. 31, 2018
Related Party Transaction [Line Items]
Related-party revenues	$ 7,893	$ 26,890
Affiliated Entity [Member] | Revolving Credit Facility [Member] | Credit Facility [Member]
Related Party Transaction [Line Items]
Interest income on Affiliate Lines of Credit	28	124
Offering-related fees and reimbursements [Member]
Related Party Transaction [Line Items]
Related-party revenues	1,027	4,316
Selling commissions [Member]
Related Party Transaction [Line Items]
Related-party revenues	407	2,177
Dealer manager and distribution fees [Member]
Related Party Transaction [Line Items]
Related-party revenues	431	1,253
Reimbursement revenue [Member]
Related Party Transaction [Line Items]
Related-party revenues	189	886
Transaction service fees and reimbursements [Member]
Related Party Transaction [Line Items]
Related-party revenues	334	4,006
Acquisition fees [Member]
Related Party Transaction [Line Items]
Related-party revenues	119	3,272
Reimbursement revenues [Member]
Related Party Transaction [Line Items]
Related-party revenues	215	734
Management fees and reimbursements [Member]
Related Party Transaction [Line Items]
Related-party revenues	6,504	18,444
Asset and property management fees and leasing fees [Member]
Related Party Transaction [Line Items]
Related-party revenues	52	53
Advisory and performance fee revenue [Member]
Related Party Transaction [Line Items]
Related-party revenues	5,023	13,624
Reimbursement revenues [Member]
Related Party Transaction [Line Items]
Related-party revenues	1,429	$ 4,767
Selling commissions allowable [Member]
Related Party Transaction [Line Items]
Selling commissions reallowed			100.00%
Selling commissions allowable [Member] | Cole REITs [Member]
Related Party Transaction [Line Items]
Selling commissions reallowed		100.00%
Dealer manager fees reimbursement [Member]
Related Party Transaction [Line Items]
Related-party revenues	$ 200	$ 500