Related Party Transactions and Arrangements - Schedule of Revenue (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Related Party Transaction [Line Items]
Related-party revenues	$ 27,078	$ 30,538	$ 81,601	$ 94,038
Affiliated Entity [Member] | Revolving Credit Facility [Member] | Credit Facility [Member]
Related Party Transaction [Line Items]
Interest income on Affiliate Lines of Credit	24	0	221	308
Offering-related fees and reimbursements [Member]
Related Party Transaction [Line Items]
Related-party revenues	3,882	9,545	12,721	32,850
Selling commissions [Member]
Related Party Transaction [Line Items]
Related-party revenues	1,816	5,008	6,336	18,112
Dealer manager and distribution fees [Member]
Related Party Transaction [Line Items]
Related-party revenues	1,278	2,237	3,766	7,292
Reimbursement revenue [Member]
Related Party Transaction [Line Items]
Related-party revenues	788	2,300	2,619	7,446
Transaction service fees and reimbursements [Member]
Related Party Transaction [Line Items]
Related-party revenues	3,964	3,499	12,110	10,297
Acquisition fees [Member]
Related Party Transaction [Line Items]
Related-party revenues	3,320	2,593	9,965	8,053
Financing coordination fee [Member]
Related Party Transaction [Line Items]
Related-party revenues	0	220	0	220
Reimbursement revenues [Member]
Related Party Transaction [Line Items]
Related-party revenues	644	686	2,145	2,024
Management fees and reimbursements [Member]
Related Party Transaction [Line Items]
Related-party revenues	19,208	17,494	56,549	50,583
Asset and property management fees and leasing fees [Member]
Related Party Transaction [Line Items]
Related-party revenues	56	53	161	159
Advisory and performance fee revenue [Member]
Related Party Transaction [Line Items]
Related-party revenues	14,532	13,011	42,318	37,621
Reimbursement revenues [Member]
Related Party Transaction [Line Items]
Related-party revenues	$ 4,620	$ 4,430	$ 14,070	$ 12,803
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	$ 600	$ 900	$ 1,600	$ 2,800
Revenue from managed real estate investment trusts, excluding fees from real estate programs [Member]
Related Party Transaction [Line Items]
Related-party revenues	$ 100	$ 500	$ 1,600	$ 1,100