United States Copper Index Fund (CPER) 10-K/A 8 Mar 21 2020 FY Annual report (amended) Financial data

Cover

Cover - USD ($)	12 Months Ended
	Dec. 31, 2020	Feb. 10, 2021	Jun. 30, 2020
Document Information [Line Items]
Document Type	10-K/A
Amendment Flag	false
Document Annual Report	true
Document Transition Report	false
Document Period End Date	Dec. 31, 2020
Document Fiscal Period Focus	FY
Document Fiscal Year Focus	2020
Current Fiscal Year End Date	--12-31
Entity File Number	001-34833
Entity Registrant Name	United States Commodity Index Funds Trust
Entity Central Index Key	0001479247
Entity Tax Identification Number	27-1537655
Entity Incorporation, State or Country Code	DE
Entity Address, Address Line One	1850 Mt. Diablo Boulevard
Entity Address, Address Line Two	Suite 640
Entity Address, City or Town	Walnut Creek
Entity Address, State or Province	CA
Entity Address, Postal Zip Code	94596
City Area Code	510
Local Phone Number	522-9600
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Public Float			$ 141,617,184
ICFR Auditor Attestation Flag	true
United States Commodity Index Fund [Member]
Document Information [Line Items]
Title of 12(b) Security	Shares of United States Commodity Index Fund
Trading Symbol	USCI
Security Exchange Name	NYSEArca
Entity Public Float			126,254,867
Entity Common Stock, Shares Outstanding		4,500,000
United States Copper Index Fund [Member]
Document Information [Line Items]
Title of 12(b) Security	Shares of United States Copper Index Fund
Trading Symbol	CPER
Security Exchange Name	NYSEArca
Entity Public Float			$ 15,362,317
Entity Common Stock, Shares Outstanding		4,750,000
Common Stock [Member]
Document Information [Line Items]
Entity Common Stock, Shares Outstanding		9,250,000