Related Party Transactions and Arrangements - Schedule of Revenue (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Related Party Transaction [Line Items]
Related-party revenues	$ 27,633	$ 32,189	$ 54,523	$ 63,500
Affiliated Entity [Member] | Revolving Credit Facility [Member] | Credit Facility [Member]
Related Party Transaction [Line Items]
Interest income	73	0	197	308
Offering-related fees and reimbursements [Member]
Related Party Transaction [Line Items]
Related-party revenues	4,523	10,914	8,839	23,305
Selling commissions [Member]
Related Party Transaction [Line Items]
Related-party revenues	2,343	6,063	4,520	13,104
Dealer manager and distribution fees [Member]
Related Party Transaction [Line Items]
Related-party revenues	1,235	2,415	2,488	5,055
Reimbursement revenue [Member]
Related Party Transaction [Line Items]
Related-party revenues	945	2,436	1,831	5,146
Transaction service fees and reimbursements [Member]
Related Party Transaction [Line Items]
Related-party revenues	4,140	4,414	8,146	6,798
Acquisition fees [Member]
Related Party Transaction [Line Items]
Related-party revenues	3,373	3,758	6,645	5,460
Reimbursement revenues [Member]
Related Party Transaction [Line Items]
Related-party revenues	767	656	1,501	1,338
Management fees and reimbursements [Member]
Related Party Transaction [Line Items]
Related-party revenues	18,897	16,861	37,341	33,089
Asset and property management fees and leasing fees [Member]
Related Party Transaction [Line Items]
Related-party revenues	52	51	105	106
Advisory and performance fee revenue [Member]
Related Party Transaction [Line Items]
Related-party revenues	14,162	12,560	27,786	24,610
Reimbursement revenues [Member]
Related Party Transaction [Line Items]
Related-party revenues	$ 4,683	$ 4,250	$ 9,450	$ 8,373
Selling commissions allowable [Member] | Cole REITs [Member]
Related Party Transaction [Line Items]
Selling commissions reallowed	100.00%	100.00%	100.00%	100.00%
Dealer manager fees reimbursement [Member]
Related Party Transaction [Line Items]
Related-party revenues	$ 500	$ 900	$ 1,000	$ 1,900
Revenue from managed real estate investment trusts, excluding fees from real estate programs [Member]
Related Party Transaction [Line Items]
Related-party revenues	$ 1,100	$ 300	$ 1,500	$ 500