Document and Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2021	Feb. 28, 2022	Jun. 30, 2021
Cover [Abstract]
Document Type	10-K
Document Annual Report	true
Document Period End Date	Dec. 31, 2021
Document Transition Report	false
Entity File Number	1-6003
Entity Registrant Name	FEDERAL SIGNAL CORPORATION
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	36-1063330
Entity Address, Address Line One	1415 West 22nd Street
Entity Address, City or Town	Oak Brook
Entity Address, State or Province	IL
Entity Address, Postal Zip Code	60523
City Area Code	630
Local Phone Number	954-2000
Title of 12(b) Security	Common Stock, par value $1.00 per share
Trading Symbol	FSS
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			$ 2,409,212,678
Entity Common Stock, Shares Outstanding		60,931,540
Documents Incorporated by Reference	Portions of the registrant’s definitive proxy statement for the 2022 Annual Meeting of Stockholders are incorporated by reference in Part III.
Entity Central Index Key	0000277509
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	FY
Amendment Flag	false