Equity - Narrative (Details)	3 Months Ended		27 Months Ended
	Mar. 31, 2018 USD ($) vote $ / shares shares	Mar. 31, 2017 $ / shares shares	Mar. 31, 2018 USD ($) $ / shares shares	Dec. 31, 2017 USD ($)	Sep. 20, 2017 USD ($)	Jul. 31, 2014 USD ($)
Class of Stock [Line Items]
Offering amount in sales of shares						$ 2,200,000,000
Number of votes (in votes) | vote	1
Percent of organizational and offering costs limit (percent)	15.00%
Days required for reimbursement of excess amounts	60 days
Organizational costs as a percentage of gross offering proceeds (percent)	82.80%
Due to related parties	$ 15,879,000		$ 15,879,000	$ 16,896,000
Minimum holding period for redemption of stock	1 year
Redemption price as percentage of Net Asset Value of outstanding shares (percent)	100.00%		100.00%
Shares of common stock redeemed (shares) | shares	1,008,029
Share Redemption Program
Class of Stock [Line Items]
Stock redeemed	$ 200,000		$ 9,400,000
Weighted average price per share (in dollars per share) | $ / shares	$ 9.15	$ 9.49	$ 9.28
Minimum holding period for redemption of stock	1 year
Maximum redemption percentage of weighted average shares outstanding (percent)	5.00%
Redemption price as percentage of Net Asset Value of outstanding shares (percent)	100.00%		100.00%
Shares of common stock redeemed (shares) | shares	217,088	148,675	1,008,028
Minimum redemption percentage	25.00%
Minimum ownership percentage under share redemption program (percent)	$ 2,500		$ 2,500
New Share Redemption Program
Class of Stock [Line Items]
Minimum holding period for redemption of stock	1 year
Quarterly redemption cap as percentage of Net Asset Value of outstanding shares (percent)	5.00%
Quarterly cap	$ 100,000		100,000
IPO
Class of Stock [Line Items]
Offering amount in sales of shares						2,000,000,000
IPO | Share Redemption Program
Class of Stock [Line Items]
Minimum holding period for redemption of stock	4 years
IPO | New Share Redemption Program
Class of Stock [Line Items]
Minimum holding period for redemption of stock	4 years
Follow-on Offering
Class of Stock [Line Items]
Offering amount in sales of shares					$ 2,200,000,000.0
Primary Offering
Class of Stock [Line Items]
Offering amount in sales of shares					2,000,000,000.0
Distribution Reinvestment Plan
Class of Stock [Line Items]
Common stock of the Company pursuant to the distribution reinvestment plan (in shares)					$ 200,000,000.0	$ 200,000,000
Value of shares tendered for redemption	$ 4,600,000		4,600,000
Organizational and offering costs incurred | IPO
Class of Stock [Line Items]
Cumulative organizational costs	2,400,000		2,400,000
Proceeds from Issuance or Sale of Equity	2,900,000
Due from related parties	76,100,000		76,100,000
Organizational and offering costs advanced by the Advisor
Class of Stock [Line Items]
Cumulative organizational costs	360,000		360,000
Due to related parties	432,000		432,000	$ 192,000
Organizational and offering costs advanced by the Advisor | If Proposed Offering Terminated
Class of Stock [Line Items]
Due to related parties	400,000		400,000
Due from related parties	2,000,000		2,000,000
Organizational and offering costs advanced by the Advisor | Due to Affiliates
Class of Stock [Line Items]
Due from related parties	1,000,000		1,000,000
Organizational and offering costs advanced by the Advisor | Other Assets
Class of Stock [Line Items]
Due from related parties	$ 1,000,000		$ 1,000,000