Capital Transactions - Summary of Shares Issued and Proceeds Received in Connection with Private Placement (Detail) - USD ($)		11 Months Ended	12 Months Ended
	Feb. 07, 2018	Dec. 31, 2018	Dec. 31, 2020	Dec. 31, 2019
Investment Company, Capital Share Transactions [Line Items]
Distributions reinvested, proceeds to company		$ 99,836	$ 2,109,793	$ 799,107
Shares Issued, Including Reinvestments		3,854,515	4,444,642	2,524,449
Net Proceeds to Company			$ 124,209,924	$ 67,991,333
Average Net Proceeds per Share		$ 25.17	$ 27.95	$ 26.93
Proceeds from Offerings
Investment Company, Capital Share Transactions [Line Items]
Shares Issued		3,850,671		2,494,425
Public Offering and Private Placement
Investment Company, Capital Share Transactions [Line Items]
Shares Issued		3,850,671	4,367,120
Gross Proceeds		$ 97,405,093
Up-front Selling Commissions and Dealer Manager Fees		(471,850)
Net Proceeds to Company		96,933,243
Net Proceeds to Company		$ 97,033,079
Distribution Reinvestment Plan [Member]
Investment Company, Capital Share Transactions [Line Items]
Stock Issued During Period, Shares, Dividend Reinvestment Plan		3,844	77,522	30,024
Distributions reinvested, proceeds to company		$ 99,836	$ 2,109,793	$ 799,107
2019 Private Offering, Follow On Private Offering and Public Offering [Member]
Investment Company, Capital Share Transactions [Line Items]
Shares Issued			4,367,120	2,494,425
Gross Proceeds			$ 125,275,212	$ 68,426,826
Up-front Selling Commissions and Dealer Manager Fees			(3,175,081)	(1,234,600)
Net Proceeds to Company			$ 122,100,131	$ 67,192,226
Class FA
Investment Company, Capital Share Transactions [Line Items]
Shares Issued, Including Reinvestments		3,258,260	569,642	1,008,488
Net Proceeds to Company		$ 81,456,500	$ 15,685,040	$ 27,586,447
Average Net Proceeds per Share		$ 25.00	$ 27.53	$ 27.35
Class FA | 2019 Private Offering [Member]
Investment Company, Capital Share Transactions [Line Items]
Shares Issued			300,000
Class FA | Private Placement
Investment Company, Capital Share Transactions [Line Items]
Shares Issued	3,300,000	3,258,260
Gross Proceeds	$ 81,700,000	$ 81,456,500
Up-front Selling Commissions and Dealer Manager Fees		0
Net Proceeds to Company		$ 81,456,500
Class FA | Distribution Reinvestment Plan [Member]
Investment Company, Capital Share Transactions [Line Items]
Stock Issued During Period, Shares, Dividend Reinvestment Plan		0	0	0
Distributions reinvested, proceeds to company		$ 0	$ 0	$ 0
Class FA | 2019 Private Placement and Follow On Private Placement [Member]
Investment Company, Capital Share Transactions [Line Items]
Shares Issued			569,642	1,008,488
Gross Proceeds			$ 15,853,000	$ 27,628,371
Net Proceeds to Company			15,685,040	27,586,447
Class FA | Follow On Private Placement [Member]
Investment Company, Capital Share Transactions [Line Items]
Up-front Selling Commissions and Dealer Manager Fees			$ (167,960)	$ (41,924)
Class A
Investment Company, Capital Share Transactions [Line Items]
Shares Issued, Including Reinvestments		192,388	369,816	477,054
Net Proceeds to Company		$ 5,064,779	$ 10,091,122	$ 12,682,767
Average Net Proceeds per Share		$ 26.33	$ 27.29	$ 26.59
Class A | Proceeds from Offerings
Investment Company, Capital Share Transactions [Line Items]
Shares Issued		190,046	334,440	463,565
Gross Proceeds		$ 5,435,093	$ 9,808,964	$ 13,294,279
Up-front Selling Commissions and Dealer Manager Fees		(430,953)	(679,465)	(970,592)
Net Proceeds to Company		$ 5,004,140	$ 9,129,499	$ 12,323,687
Class A | Distribution Reinvestment Plan [Member]
Investment Company, Capital Share Transactions [Line Items]
Stock Issued During Period, Shares, Dividend Reinvestment Plan		2,342	35,376	13,489
Distributions reinvested, proceeds to company		$ 60,639	$ 961,623	$ 359,080
Class T
Investment Company, Capital Share Transactions [Line Items]
Shares Issued, Including Reinvestments		31,452	481,784	167,210
Net Proceeds to Company		$ 820,613	$ 13,075,429	$ 4,478,330
Average Net Proceeds per Share		$ 26.09	$ 27.14	$ 26.78
Class T | Proceeds from Offerings
Investment Company, Capital Share Transactions [Line Items]
Shares Issued		31,432	473,344	166,277
Gross Proceeds		$ 861,000	$ 13,486,208	$ 4,675,452
Up-front Selling Commissions and Dealer Manager Fees		(40,897)	(640,595)	(222,084)
Net Proceeds to Company		$ 820,103	$ 12,845,613	$ 4,453,368
Class T | Distribution Reinvestment Plan [Member]
Investment Company, Capital Share Transactions [Line Items]
Stock Issued During Period, Shares, Dividend Reinvestment Plan		20	8,440	933
Distributions reinvested, proceeds to company		$ 510	$ 229,816	$ 24,962
Class D
Investment Company, Capital Share Transactions [Line Items]
Shares Issued, Including Reinvestments		122,889	152,248	182,928
Net Proceeds to Company		$ 3,188,533	$ 4,118,666	$ 4,822,008
Average Net Proceeds per Share		$ 25.95	$ 27.05	$ 26.36
Class D | Proceeds from Offerings
Investment Company, Capital Share Transactions [Line Items]
Shares Issued		121,797	143,074	176,604
Gross Proceeds		$ 3,160,000	$ 3,873,660	$ 4,655,674
Up-front Selling Commissions and Dealer Manager Fees		0	0	0
Net Proceeds to Company		$ 3,160,000	$ 3,873,660	$ 4,655,674
Class D | Distribution Reinvestment Plan [Member]
Investment Company, Capital Share Transactions [Line Items]
Stock Issued During Period, Shares, Dividend Reinvestment Plan		1,092	9,174	6,324
Distributions reinvested, proceeds to company		$ 28,533	$ 245,006	$ 166,334
Class I
Investment Company, Capital Share Transactions [Line Items]
Shares Issued, Including Reinvestments		249,526	1,100,766	688,769
Net Proceeds to Company		$ 6,502,654	$ 30,567,081	$ 18,421,781
Average Net Proceeds per Share		$ 26.06	$ 27.77	$ 26.75
Class I | Proceeds from Offerings
Investment Company, Capital Share Transactions [Line Items]
Shares Issued		249,136	1,076,234	679,491
Gross Proceeds		$ 6,492,500	$ 29,893,733	$ 18,173,050
Up-front Selling Commissions and Dealer Manager Fees		0	0	0
Net Proceeds to Company		$ 6,492,500	$ 29,893,733	$ 18,173,050
Class I | Distribution Reinvestment Plan [Member]
Investment Company, Capital Share Transactions [Line Items]
Stock Issued During Period, Shares, Dividend Reinvestment Plan		390	24,532	9,278
Distributions reinvested, proceeds to company		$ 10,154	$ 673,348	$ 248,731