Document and Entity Information - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Mar. 09, 2017	Jun. 30, 2016
Document And Entity Information
Entity Registrant Name	PCM, INC.
Entity Central Index Key	0000937941
Document Type	10-K
Document Period End Date	Dec. 31, 2016
Amendment Flag	false
Current Fiscal Year End Date	--12-31
Entity Filer Category	Accelerated Filer
Entity a Well-known Seasoned Issuer	No
Entity a Voluntary Filer	No
Entity Current Reporting Status	Yes
Entity Public Float			$ 97,800
Entity Common Stock, Shares Outstanding		12,477,154
Trading Symbol	PCMI
Document Fiscal Period Focus	FY
Document Fiscal Year Focus	2016