Cover Page - shares	3 Months Ended
	Mar. 31, 2020	Jun. 01, 2020
Cover [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Mar. 31, 2020
Document Transition Report	false
Entity File Number	000-53912
Entity Registrant Name	HARTMAN SHORT TERM INCOME PROPERTIES XX, INC.
Entity Incorporation, State or Country Code	MD
Entity Tax Identification Number	26-3455189
Entity Address, Address Line One	2909 Hillcroft
Entity Address, Address Line Two	Suite 420
Entity Address, City or Town	Houston
Entity Address, State or Province	TX
Entity Address, Postal Zip Code	77057
City Area Code	713
Local Phone Number	467-2222
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Smaller Reporting Company	true
Emerging Growth Company	true
Entity Shell Company	false
Extended Transition Period	true
Entity Common Stock, Shares Outstanding		18,417,687
Amendment Flag	false
Entity Central Index Key	0001446687
Current Fiscal Year End Date	--12-31
Entity Filer Category	Non-accelerated Filer
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	Q1