Document and Entity Information - USD ($) $ in Billions	12 Months Ended
	Dec. 31, 2023	Feb. 01, 2024	Jun. 30, 2023
Cover [Abstract]
Document Type	10-K
Document Annual Report	true
Document Period End Date	Dec. 31, 2023
Document Transition Report	false
Entity File Number	1-13998
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	76-0479645
Entity Address, Address Line One	19001 Crescent Springs Drive
Entity Address, City or Town	Kingwood,
Entity Address, State or Province	TX
Entity Address, Postal Zip Code	77339
City Area Code	281
Local Phone Number	358-8986
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 Common Stock, Shares Outstanding		37,289,427
Entity Public Float			$ 4.3
Entity Registrant Name	Insperity, Inc.
Entity Central Index Key	0001000753
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2023
Document Fiscal Period Focus	FY
Document Financial Statement Error Correction [Flag]	false
Amendment Flag	false
Auditor Firm ID	42
Auditor Name	Ernst & Young LLP
Auditor Location	Houston, Texas
Entity Information [Line Items]
Entity Registrant Name	Insperity, Inc.
Entity Emerging Growth Company	false
Entity Small Business	false
Document Annual Report	true
Common Stock [Member]
Entity Information [Line Items]
Title of 12(b) Security	Common Stock, $0.01 par value per share
Trading Symbol	NSP
Security Exchange Name	NYSE