Basis of Presentation and Description of Company	9 Months Ended
Sep. 30, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation and Description of Company	1. Basis of Presentation and Description of Company PCM, Inc. is a leading multi-vendor provider of technology solutions, including hardware products, software and services, offered through our dedicated sales force, ecommerce channels and technology services teams. Since our founding in 1987, we have served our customers by offering products and services from vendors such as Adobe, Apple, Cisco, Dell, Hewlett Packard Enterprise, HP Inc., Lenovo, Microsoft, Oracle, Symantec and VMware. We provide our customers with comprehensive solutions incorporating leading products and services across a variety of technology practices and platforms such as cloud, security, data center, networking, collaboration and mobility. Our sales and marketing efforts allow our vendor partners to reach multiple customer segments including small, medium and enterprise businesses, state, local and federal governments and educational institutions. We have prepared the unaudited condensed consolidated financial statements included herein pursuant to the rules and regulations of the Securities and Exchange Commission (“SEC”) and in conformity with accounting principles generally accepted in the United States of America, or GAAP, which requires us to make estimates and assumptions that affect amounts reported herein. We base our estimates and assumptions on historical experience and on various other factors that we believe to be reasonable under the circumstances. Due to the inherent uncertainty involved in making estimates, our actual results reported in future periods may be affected by changes in those estimates. Certain information and footnote disclosures normally included in financial statements prepared in accordance with GAAP have been condensed or omitted pursuant to such rules and regulations for interim financial reporting. In the opinion of management, all adjustments, consisting only of normal recurring items which are necessary for a fair presentation, have been included. The results for interim periods are not necessarily indicative of the results that may be expected for any other interim period or for the full year. These unaudited condensed consolidated financial statements should be read in conjunction with the audited consolidated financial statements and the notes thereto included in our Annual Report on Form 10-K for the year ended December 31, 2017 filed with the SEC. We operate in four reportable segments: Commercial, Public Sector, Canada and United Kingdom. Our reportable operating segments are primarily aligned based upon our reporting of results as used by our chief operating decision maker in evaluating the operating results and performance of our company. We include corporate related expenses such as legal, accounting, information technology, product management and other administrative costs that are not otherwise included in our reportable operating segments in Corporate & Other. We sell primarily to customers in the United States, Canada and the UK, and maintain offices in the United States, Canada and the UK, as well as in the Philippines. During the three months ended September 30, 2018, we generated approximately 75% of our revenue in our Commercial segment, 13% of our revenue in our Public Sector segment, 9% of our revenue in our Canada segment and 3% of our revenue in our United Kingdom segment. During the nine months ended September 30, 2018, we generated approximately 75% of our revenue in our Commercial segment, 12% of our revenue in our Public Sector segment, 9% of our revenue in our Canada segment and 3% of our revenue in our United Kingdom segment. Our Commercial segment sells complex technology solutions to commercial businesses in the United States, using multiple sales channels, including a field relationship-based selling model, an outbound phone based sales force, a field services organization and online extranets. Our Public Sector segment consists of sales made primarily to federal, state and local governments, as well as educational institutions. The Public Sector segment utilizes an outbound phone and field relationship-based selling model, as well as contract and bid business development teams and an online extranet. Our Canada segment consists of sales made to customers in the Canadian market beginning as of the respective dates of our acquisition of Acrodex and certain assets of Systemax in October and December 2015, respectively, as well as the acquisition of Stratiform in December 2016. Our United Kingdom segment consists of results of our UK subsidiary, PCM Technology Solutions UK, Ltd. (“PCM UK”), and its wholly-owned subsidiaries, which serve as our hub for the UK and the rest of Europe. PCM UK commenced its sales operations in May 2017.

Basis of Presentation and Description of Company

9 Months Ended

Sep. 30, 2018

Organization, Consolidation and Presentation of Financial Statements [Abstract]

Basis of Presentation and Description of Company

1. Basis of Presentation and Description of Company

PCM, Inc. is a leading multi-vendor provider of technology solutions, including hardware products, software and services, offered through our dedicated sales force, ecommerce channels and technology services teams. Since our founding in 1987, we have served our customers by offering products and services from vendors such as Adobe, Apple, Cisco, Dell, Hewlett Packard Enterprise, HP Inc., Lenovo, Microsoft, Oracle, Symantec and VMware. We provide our customers with comprehensive solutions incorporating leading products and services across a variety of technology practices and platforms such as cloud, security, data center, networking, collaboration and mobility. Our sales and marketing efforts allow our vendor partners to reach multiple customer segments including small, medium and enterprise businesses, state, local and federal governments and educational institutions.

We have prepared the unaudited condensed consolidated financial statements included herein pursuant to the rules and regulations of the Securities and Exchange Commission (“SEC”) and in conformity with accounting principles generally accepted in the United States of America, or GAAP, which requires us to make estimates and assumptions that affect amounts reported herein. We base our estimates and assumptions on historical experience and on various other factors that we believe to be reasonable under the circumstances. Due to the inherent uncertainty involved in making estimates, our actual results reported in future periods may be affected by changes in those estimates. Certain information and footnote disclosures normally included in financial statements prepared in accordance with GAAP have been condensed or omitted pursuant to such rules and regulations for interim financial reporting. In the opinion of management, all adjustments, consisting only of normal recurring items which are necessary for a fair presentation, have been included. The results for interim periods are not necessarily indicative of the results that may be expected for any other interim period or for the full year. These unaudited condensed consolidated financial statements should be read in conjunction with the audited consolidated financial statements and the notes thereto included in our Annual Report on Form 10-K for the year ended December 31, 2017 filed with the SEC.

We operate in four reportable segments: Commercial, Public Sector, Canada and United Kingdom. Our reportable operating segments are primarily aligned based upon our reporting of results as used by our chief operating decision maker in evaluating the operating results and performance of our company. We include corporate related expenses such as legal, accounting, information technology, product management and other administrative costs that are not otherwise included in our reportable operating segments in Corporate & Other.

We sell primarily to customers in the United States, Canada and the UK, and maintain offices in the United States, Canada and the UK, as well as in the Philippines. During the three months ended September 30, 2018, we generated approximately 75% of our revenue in our Commercial segment, 13% of our revenue in our Public Sector segment, 9% of our revenue in our Canada segment and 3% of our revenue in our United Kingdom segment. During the nine months ended September 30, 2018, we generated approximately 75% of our revenue in our Commercial segment, 12% of our revenue in our Public Sector segment, 9% of our revenue in our Canada segment and 3% of our revenue in our United Kingdom segment.

Our Commercial segment sells complex technology solutions to commercial businesses in the United States, using multiple sales channels, including a field relationship-based selling model, an outbound phone based sales force, a field services organization and online extranets.

Our Public Sector segment consists of sales made primarily to federal, state and local governments, as well as educational institutions. The Public Sector segment utilizes an outbound phone and field relationship-based selling model, as well as contract and bid business development teams and an online extranet.

Our Canada segment consists of sales made to customers in the Canadian market beginning as of the respective dates of our acquisition of Acrodex and certain assets of Systemax in October and December 2015, respectively, as well as the acquisition of Stratiform in December 2016.

Our United Kingdom segment consists of results of our UK subsidiary, PCM Technology Solutions UK, Ltd. (“PCM UK”), and its wholly-owned subsidiaries, which serve as our hub for the UK and the rest of Europe. PCM UK commenced its sales operations in May 2017.