Summary of Significant Accounting Policies (Policies)	9 Months Ended
Sep. 30, 2012
Summary of Significant Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The accompanying unaudited condensed consolidated financial statements include the accounts of Saia, Inc. and its wholly-owned subsidiaries (together, the Company or Saia). All significant intercompany accounts and transactions have been eliminated in the condensed consolidated financial statements. The condensed consolidated financial statements include the financial position and results of operations of Robart Transportation, Inc. and its subsidiary, The RL Service Group, LLC (the Robart Companies) since its acquisition date of July 2, 2012 (See Note 5). The condensed consolidated financial statements have been prepared by the Company without audit by the independent registered public accounting firm. In the opinion of management, all normal recurring adjustments necessary for a fair presentation of the condensed consolidated statements of financial position, results of operations and cash flows for the interim periods included herein have been made. These interim condensed consolidated financial statements of the Company have been prepared in accordance with U.S. generally accepted accounting principles for interim financial information, the instructions to Quarterly Report on Form 10-Q and Rule 10-01 of Regulation S-X. Certain information and note disclosures normally included in financial statements prepared in accordance with U.S. generally accepted accounting principles have been condensed or omitted from these statements. The accompanying condensed consolidated financial statements should be read in conjunction with the Company’s Annual Report on Form 10-K for the year ended December 31, 2011. Operating results for the quarters and nine months ended September 30, 2012 are not necessarily indicative of the results of operations that may be expected for the year ended December 31, 2012.
Business	Business The Company offers customers a wide range of less-than-truckload, non-asset truckload, expedited and logistics services across the United States through its wholly-owned subsidiaries. Effective October 1, 2012, the Company’s subsidiaries were as follows: Saia Motor Freight Line, LLC, doing business as Saia LTL Freight; Saia TL Plus, Inc., formerly Robart Transportation, Inc., and Saia Logistics Services, LLC, formerly The RL Services Group, LLC.
New Accounting Pronouncements	New Accounting Pronouncements There are no new accounting pronouncements pending adoption as of September 30, 2012 that the Company believes would have a significant impact on its condensed consolidated financial statements.

Summary of Significant Accounting Policies (Policies)

9 Months Ended

Sep. 30, 2012

Summary of Significant Accounting Policies [Abstract]

Basis of Presentation

The accompanying unaudited condensed consolidated financial statements include the accounts of Saia, Inc. and its wholly-owned subsidiaries (together, the Company or Saia). All significant intercompany accounts and transactions have been eliminated in the condensed consolidated financial statements. The condensed consolidated financial statements include the financial position and results of operations of Robart Transportation, Inc. and its subsidiary, The RL Service Group, LLC (the Robart Companies) since its acquisition date of July 2, 2012 (See Note 5).

The condensed consolidated financial statements have been prepared by the Company without audit by the independent registered public accounting firm. In the opinion of management, all normal recurring adjustments necessary for a fair presentation of the condensed consolidated statements of financial position, results of operations and cash flows for the interim periods included herein have been made. These interim condensed consolidated financial statements of the Company have been prepared in accordance with U.S. generally accepted accounting principles for interim financial information, the instructions to Quarterly Report on Form 10-Q and Rule 10-01 of Regulation S-X. Certain information and note disclosures normally included in financial statements prepared in accordance with U.S. generally accepted accounting principles have been condensed or omitted from these statements. The accompanying condensed consolidated financial statements should be read in conjunction with the Company’s Annual Report on Form 10-K for the year ended December 31, 2011. Operating results for the quarters and nine months ended September 30, 2012 are not necessarily indicative of the results of operations that may be expected for the year ended December 31, 2012.

Business

Business

The Company offers customers a wide range of less-than-truckload, non-asset truckload, expedited and logistics services across the United States through its wholly-owned subsidiaries. Effective October 1, 2012, the Company’s subsidiaries were as follows: Saia Motor Freight Line, LLC, doing business as Saia LTL Freight; Saia TL Plus, Inc., formerly Robart Transportation, Inc., and Saia Logistics Services, LLC, formerly The RL Services Group, LLC.

New Accounting Pronouncements

New Accounting Pronouncements

There are no new accounting pronouncements pending adoption as of September 30, 2012 that the Company believes would have a significant impact on its condensed consolidated financial statements.