Document and Entity Information - shares	6 Months Ended
	Jun. 30, 2025	Jul. 23, 2025
Document And Entity Information
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Jun. 30, 2025
Document Transition Report	false
Securities Act File Number	0-23827
Entity Registrant Name	PC CONNECTION, INC.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	02-0513618
Entity Address, Address Line One	730 Milford Road
Entity Address, City or Town	Merrimack
Entity Address, State or Province	NH
Entity Address, Postal Zip Code	03054
City Area Code	603
Local Phone Number	683-2000
Title of 12(b) Security	Common Stock, $0.01 par value
Trading Symbol	CNXN
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		25,389,003
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2025
Document Fiscal Period Focus	Q2
Entity Central Index Key	0001050377
Amendment Flag	false