Document and Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2020	Feb. 17, 2021	Jun. 30, 2020
Cover [Abstract]
Document Type	10-K
Document Annual Report	true
Document Period End Date	Dec. 31, 2020
Document Transition Report	false
Entity File Number	1-4801
Entity Registrant Name	BARNES GROUP INC.
Entity Central Index Key	0000009984
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	FY
Amendment Flag	false
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	06-0247840
Entity Address, Address Line One	123 Main Street
Entity Address, City or Town	Bristol
Entity Address, State or Province	CT
Entity Address, Postal Zip Code	06010
City Area Code	860
Local Phone Number	583-7070
Title of 12(b) Security	Common Stock, par value $0.01 per share
Trading Symbol	B
Security Exchange Name	NYSE
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
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
ICFR Auditor Attestation Flag	true
Entity Shell Company	false
Entity Public Float			$ 1,839,749,332
Entity Common Stock, Shares Outstanding		50,649,227
Documents Incorporated by Reference	Portions of the registrant’s definitive proxy statement to be delivered to stockholders in connection with the Annual Meeting of Stockholders to be held on May 7, 2021 are incorporated by reference into Part III.