Cover - shares	6 Months Ended
	Jun. 30, 2020	Aug. 05, 2020
Entity Information [Line Items]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Jun. 30, 2020
Document Transition Report	false
Entity File Number	001-38260
Entity Registrant Name	BP Midstream Partners LP
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	82-1646447
Entity Address, Address Line One	501 Westlake Park Boulevard
Entity Address, City or Town	Houston
Entity Address, State or Province	TX
Entity Address, Postal Zip Code	77079
City Area Code	281
Local Phone Number	366-2000
Title of 12(b) Security	Common Units, Representing Limited Partner Interests
Trading Symbol	BPMP
Security Exchange Name	NYSE
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Current Fiscal Year End Date	--12-31
Amendment Flag	false
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	Q2
Entity Central Index Key	0001708301
Common Units
Entity Information [Line Items]
Entity Common Stock, Shares Outstanding		52,402,967
Subordinated Units
Entity Information [Line Items]
Entity Common Stock, Shares Outstanding		52,375,535