Stockholders' Equity - Summary of Issuances and Redemptions of Common Stock (Details) - USD ($) $ / shares in Units, shares in Thousands	1 Months Ended	12 Months Ended
	Nov. 30, 2017	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Oct. 31, 2017
Increase (Decrease) in Stockholders' Equity
Beginning balance, value		$ 278,733,000
Ending balance, value		$ 591,521,000	$ 278,733,000
Tender Offer
Increase (Decrease) in Stockholders' Equity
Maximum proceeds from issuance					$ 200,000,000.0
Price per share (in USD per share)					$ 9.69
Shares redeemed (in shares)	1,900
Aggregate cost of redeemed shares	$ 18,700,000
Common Shares
Increase (Decrease) in Stockholders' Equity
Beginning balance, shares (in shares)		43,584	39,256	26,543
Beginning balance, value		$ 44,000	$ 39,000	$ 26,000
Issuance of common shares, shares (in shares)		39,805	5,601	14,807
Issuance of common shares, value		$ 41,000	$ 7,000	$ 15,000
Redemption of common shares, shares (in shares)		(1,542)	(1,273)	(2,094)
Redemption of common shares, value		$ (2,000)	$ (2,000)	$ (2,000)
Ending balance, shares (in shares)		81,847	43,584	39,256
Ending balance, value		$ 83,000	$ 44,000	$ 39,000
Class JX
Increase (Decrease) in Stockholders' Equity
Beginning balance, shares (in shares)		0
Ending balance, shares (in shares)		0	0
Class JX | Common Shares
Increase (Decrease) in Stockholders' Equity
Issuance of common shares, shares (in shares)		0
Redemption of common shares, shares (in shares)		0
Ending balance, shares (in shares)		0
Class S
Increase (Decrease) in Stockholders' Equity
Beginning balance, shares (in shares)		0
Ending balance, shares (in shares)		0	0
Class S | Common Shares
Increase (Decrease) in Stockholders' Equity
Issuance of common shares, shares (in shares)		0
Redemption of common shares, shares (in shares)		0
Ending balance, shares (in shares)		0
Class AX
Increase (Decrease) in Stockholders' Equity
Beginning balance, shares (in shares)		19,123
Ending balance, shares (in shares)		18,885	19,123
Class AX | Common Shares
Increase (Decrease) in Stockholders' Equity
Beginning balance, shares (in shares)		19,123	19,206	16,469
Beginning balance, value		$ 19,000	$ 19,000	$ 16,000
Issuance of common shares, shares (in shares)		532	566	3,874
Issuance of common shares, value		$ 1,000	$ 1,000	$ 4,000
Redemption of common shares, shares (in shares)		(770)	(649)	(1,137)
Redemption of common shares, value		$ (1,000)	$ (1,000)	$ (1,000)
Ending balance, shares (in shares)		18,885	19,123	19,206
Ending balance, value		$ 19,000	$ 19,000	$ 19,000
Class TX
Increase (Decrease) in Stockholders' Equity
Beginning balance, shares (in shares)		19,969
Ending balance, shares (in shares)		19,901	19,969
Class TX | Common Shares
Increase (Decrease) in Stockholders' Equity
Beginning balance, shares (in shares)		19,969	19,958	10,074
Beginning balance, value		$ 21,000	$ 20,000	$ 10,000
Issuance of common shares, shares (in shares)		611	635	10,841
Issuance of common shares, value		$ 2,000	$ 2,000	$ 11,000
Redemption of common shares, shares (in shares)		(679)	(624)	(957)
Redemption of common shares, value		$ (1,000)	$ (1,000)	$ (1,000)
Ending balance, shares (in shares)		19,901	19,969	19,958
Ending balance, value		$ 22,000	$ 21,000	$ 20,000
Class IX
Increase (Decrease) in Stockholders' Equity
Beginning balance, shares (in shares)		96
Ending balance, shares (in shares)		91	96
Class IX | Common Shares
Increase (Decrease) in Stockholders' Equity
Beginning balance, shares (in shares)		96	92	0
Beginning balance, value		$ 0	$ 0	$ 0
Issuance of common shares, shares (in shares)		4	4	92
Issuance of common shares, value		$ 0	$ 0	$ 0
Redemption of common shares, shares (in shares)		(9)	0	0
Redemption of common shares, value		$ 0	$ 0	$ 0
Ending balance, shares (in shares)		91	96	92
Ending balance, value		$ 0	$ 0	$ 0
Class T
Increase (Decrease) in Stockholders' Equity
Beginning balance, shares (in shares)		2,858
Ending balance, shares (in shares)		28,837	2,858
Class T | Common Shares
Increase (Decrease) in Stockholders' Equity
Beginning balance, shares (in shares)		2,858	0
Beginning balance, value		$ 3,000	$ 0
Issuance of common shares, shares (in shares)		26,008	2,858
Issuance of common shares, value		$ 26,000	$ 3,000
Redemption of common shares, shares (in shares)		(29)	0
Redemption of common shares, value		$ 0	$ 0
Ending balance, shares (in shares)		28,837	2,858	0
Ending balance, value		$ 29,000	$ 3,000	$ 0
Class D
Increase (Decrease) in Stockholders' Equity
Beginning balance, shares (in shares)		1,479
Ending balance, shares (in shares)		6,927	1,479
Class D | Common Shares
Increase (Decrease) in Stockholders' Equity
Beginning balance, shares (in shares)		1,479	0
Beginning balance, value		$ 1,000	$ 0
Issuance of common shares, shares (in shares)		5,471	1,479
Issuance of common shares, value		$ 5,000	$ 1,000
Redemption of common shares, shares (in shares)		(23)	0
Redemption of common shares, value		$ 0	$ 0
Ending balance, shares (in shares)		6,927	1,479	0
Ending balance, value		$ 6,000	$ 1,000	$ 0
Class I
Increase (Decrease) in Stockholders' Equity
Beginning balance, shares (in shares)		59
Ending balance, shares (in shares)		7,206	59
Class I | Common Shares
Increase (Decrease) in Stockholders' Equity
Beginning balance, shares (in shares)		59	0
Beginning balance, value		$ 0	$ 0
Issuance of common shares, shares (in shares)		7,179	59
Issuance of common shares, value		$ 7,000	$ 0
Redemption of common shares, shares (in shares)		(32)	0
Redemption of common shares, value		$ 0	$ 0
Ending balance, shares (in shares)		7,206	59	0
Ending balance, value		$ 7,000	$ 0	$ 0