Cover - shares	9 Months Ended
	Sep. 30, 2020	Oct. 29, 2020
Cover [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Sep. 30, 2020
Document Transition Report	false
Entity File Number	000-26058
Entity Registrant Name	Kforce Inc
Entity Incorporation, State or Country Code	FL
Entity Tax Identification Number	59-3264661
Entity Address, Address Line One	1001 East Palm Avenue
Entity Address, City or Town	Tampa
Entity Address, State or Province	FL
Entity Address, Postal Zip Code	33605
City Area Code	813
Local Phone Number	552-5000
Title of 12(b) Security	Common Stock, $0.01 per share
Trading Symbol	KFRC
Security Exchange Name	NASDAQ
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
Entity Common Stock, Shares Outstanding		21,956,078
Amendment Flag	false
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	Q3
Current Fiscal Year End Date	--12-31
Entity Central Index Key	0000930420