Business and Organization (Details)			9 Months Ended	68 Months Ended
	Jan. 19, 2016 USD ($) shares	Feb. 02, 2015 USD ($) shares	Sep. 30, 2020 USD ($) employee $ / shares shares	Sep. 30, 2020 USD ($) employee $ / shares shares	Dec. 31, 2019 $ / shares shares	Dec. 31, 2015 shares
Class of Stock [Line Items]
Common stock, shares authorized (in shares) | shares			400,000,000	400,000,000	400,000,000
Common stock, par value (in dollars per share) | $ / shares			$ 0.01	$ 0.01	$ 0.01
Preferred stock, shares authorized (in shares) | shares			50,000,000.0	50,000,000.0	50,000,000
Preferred stock, par value (in dollars per share) | $ / shares			$ 0.01	$ 0.01	$ 0.01
Proceeds from initial offering | $		$ 1,100,000,000
Number of shares issued (in shares) | shares		108,600,000
Follow-on public offering | $	$ 700,000,000.0
Net proceeds from issuance of common stock | $				$ 2,000,000,000.0
Number of employees | employee			0	0
Dividend Reinvestment Plan
Class of Stock [Line Items]
Number of shares issued (in shares) | shares	4,200,000	2,000,000.0
Shares available (in shares) | shares						30,000,000.0
Net proceeds from issuance of common stock | $				$ 232,600,000
Follow-on Primary Offering
Class of Stock [Line Items]
Number of shares issued (in shares) | shares	64,900,000
Advisor
Class of Stock [Line Items]
Non-controlling interest investment in operating partnership | $			$ 1,000
Special Unit Holder
Class of Stock [Line Items]
Non-controlling interest investment in operating partnership | $			$ 1,000
Primary Beneficiary
Class of Stock [Line Items]
Limited partnership interest in operating partnership			99.99%