XML 27 R1.htm IDEA: XBRL DOCUMENT v3.20.4
Document and Entity Information - USD ($)
$ in Billions
 12 Months Ended
Dec. 31, 2020
Feb. 04, 2021
Jun. 30, 2020
Cover [Abstract]      
Document Type 10-K    
Document Annual Report true    
Document Transition Report false    
Document Period End Date Dec. 31, 2020    
Entity Interactive Data Current Yes    
Document Fiscal Year Focus 2020    
Document Fiscal Period Focus FY    
ICFR Auditor Attestation Flag true    
Amendment Flag false    
Entity Shell Company false    
Entity File Number 1-13998    
Entity Registrant Name Insperity, Inc.    
Entity Central Index Key 0001000753    
Current Fiscal Year End Date --12-31    
Entity Incorporation, State or Country Code DE    
Entity Tax Identification Number 76-0479645    
Entity Current Reporting Status Yes    
Entity Well-known Seasoned Issuer Yes    
Entity Voluntary Filers No    
Entity Small Business false    
Entity Public Float     $ 2.3
Entity Filer Category Large Accelerated Filer    
Entity Emerging Growth Company false    
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 Listings [Line Items]      
Entity Common Stock, Shares Outstanding   38,212,701  
Common Stock [Member]      
Entity Listings [Line Items]      
Title of 12(b) Security Common Stock, Par value $0.01 per share    
Trading Symbol NSP    
Security Exchange Name NYSE    
Rights [Member]      
Entity Listings [Line Items]      
Title of 12(b) Security Rights to Purchase Shares    
Trading Symbol NSP    
Security Exchange Name NYSE