Basis of Presentation	3 Months Ended
Mar. 28, 2015
Organization, Consolidation and Presentation of Financial Statements [Abstract]
BASIS OF PRESENTATION	BASIS OF PRESENTATION The accompanying condensed consolidated financial statements are unaudited and have been prepared by Charles River Laboratories International, Inc. (the Company) in accordance with accounting principles generally accepted in the United States (U.S. GAAP) and pursuant to Rule 10-01 of Regulation S-X. The year-end condensed consolidated balance sheet data was derived from the Company’s audited financial statements, but does not include all disclosures required by U.S. GAAP. These interim condensed consolidated financial statements should be read in conjunction with the Company’s Annual Report on Form 10-K for the year ended December 27, 2014. The condensed consolidated financial statements, in the opinion of management, reflect all normal and recurring adjustments necessary for a fair statement of our financial position and results of operations. Certain reclassifications have been made to prior year amounts to conform to the current year presentation. The Company’s fiscal year is the twelve-month period ending the last Saturday in December. Segment Reporting During the three months ended June 28, 2014, following its acquisition of the contract research organization (CRO) services division of Galapagos N.V. (Argenta and BioFocus), the Company increased the number of its reportable segments to ensure alignment with the Company’s view of the business. The change in the Company’s reporting segments is described in Note 1, “Description of Business and Summary of Significant Accounting Policies,” in the 2014 Annual Report on Form 10-K. Use of Estimates The preparation of condensed consolidated financial statements in accordance with U.S. GAAP requires that the Company makes estimates and judgments that may affect the reported amounts of assets, liabilities, revenues, expenses, and related disclosure of contingent assets and liabilities. On an on-going basis, the Company evaluates its estimates, judgments and methodologies. The Company bases its estimates on historical experience and on various other assumptions that are believed to be reasonable, the results of which form the basis for making judgments about the carrying values of assets and liabilities. Actual results may differ from these estimates under different assumptions or conditions. Changes in estimates are reflected in reported results in the period in which they become known. Consolidation The Company’s consolidated financial statements reflect its financial statements and those of its subsidiaries in which the Company holds a controlling financial interest. For consolidated entities in which the Company owns or is exposed to less than 100% of the economics, the Company records net income (loss) attributable to noncontrolling interests in its consolidated statements of income equal to the percentage of the economic or ownership interest retained in such entities by the respective noncontrolling parties. Intercompany balances and transactions are eliminated in consolidation. Summary of Significant Accounting Policies The Company’s significant accounting policies are described in Note 1, “Description of Business and Summary of Significant Accounting Policies,” in the 2014 Annual Report on Form 10-K. New Accounting Pronouncements In February 2015, the Financial Accounting Standards Board (FASB) issued Accounting Standards Update (ASU) 2015-02, “Amendments to the Consolidation Analysis,” which amends existing consolidation requirements. The guidance affects reporting entities that are required to evaluate whether they should consolidate certain legal entities. Specifically, the guidance amends (i) the identification of variable interests (fees paid to a decision maker or service provider), (ii) the variable interest entity characteristics for a limited partnership or similar entity and (iii) the primary beneficiary determination. The ASU is effective for fiscal years beginning after December 15, 2015, and interim periods within those fiscal years. Early adoption is permitted. The adoption of this standard is not expected to have a significant impact on the Company’s financial position or results of operations. In April 2015, the FASB issued ASU 2015-03 “Simplifying the Presentation of Debt Issuance Costs,” which requires debt issuance costs to be presented in the balance sheet as a direct deduction from the carrying value of the associated debt liability, consistent with the presentation of debt discounts or premiums. The ASU is effective for fiscal years beginning after December 15, 2015, and interim periods within those fiscal years. Early adoption is permitted for financial statements that have not been previously issued. The adoption of this standard is not expected to have a significant impact on the Company’s financial position or results of operations. In April 2015, FASB issued ASU 2015-04 “Practical Expedient for the Measurement Date of an Employer’s Defined Benefit Obligation and Plan Assets” to provide a practical expedient related to the measurement date of the defined benefit plan assets and obligations. The practical expedient allows employers with fiscal year-end dates that do not coincide with a calendar month end to measure pension and post-retirement benefit plan assets and obligations as of the calendar month-end date closest to the fiscal year end. The standard requires entities which elect the practical expedient to adjust the measurement of benefit plan assets and obligations for contributions or significant events between the month-end measurement date and the entity fiscal year end. The ASU is effective for fiscal years beginning after December 15, 2015, and interim periods within those fiscal years. Early adoption is permitted. The Company is still evaluating the impact the election of the practical expedient would have on its consolidated financial statements and related disclosures. In May 2014, the FASB issued ASU 2014-09, “Revenue from Contracts with Customers.” The standard requires an entity to recognize the amount of revenue to which it expects to be entitled for the transfer of promised goods or services to customers. The standard will replace most existing revenue recognition guidance in U.S. GAAP when it becomes effective and permits the use of either the retrospective or cumulative effect transition method. The ASU is effective for annual and interim periods beginning after December 15, 2016. On April 1, 2015, the FASB voted on to propose a deferral of the effective date of the ASU by one year, but to permit entities to adopt one year earlier if they choose. The proposed deferral is not a final decision and is still subject to the FASB’s due process requirement, which includes a period for public comments. The Company has not yet selected a transition method and is evaluating the impact the adoption will have on its consolidated financial statements and related disclosures.

BASIS OF PRESENTATION

The accompanying condensed consolidated financial statements are unaudited and have been prepared by Charles River Laboratories International, Inc. (the Company) in accordance with accounting principles generally accepted in the United States (U.S. GAAP) and pursuant to Rule 10-01 of Regulation S-X. The year-end condensed consolidated balance sheet data was derived from the Company’s audited financial statements, but does not include all disclosures required by U.S. GAAP. These interim condensed consolidated financial statements should be read in conjunction with the Company’s Annual Report on Form 10-K for the year ended December 27, 2014. The condensed consolidated financial statements, in the opinion of management, reflect all normal and recurring adjustments necessary for a fair statement of our financial position and results of operations. Certain reclassifications have been made to prior year amounts to conform to the current year presentation. The Company’s fiscal year is the twelve-month period ending the last Saturday in December.

Segment Reporting

During the three months ended June 28, 2014, following its acquisition of the contract research organization (CRO) services division of Galapagos N.V. (Argenta and BioFocus), the Company increased the number of its reportable segments to ensure alignment with the Company’s view of the business. The change in the Company’s reporting segments is described in Note 1, “Description of Business and Summary of Significant Accounting Policies,” in the 2014 Annual Report on Form 10-K.

Use of Estimates

The preparation of condensed consolidated financial statements in accordance with U.S. GAAP requires that the Company makes estimates and judgments that may affect the reported amounts of assets, liabilities, revenues, expenses, and related disclosure of contingent assets and liabilities. On an on-going basis, the Company evaluates its estimates, judgments and methodologies. The Company bases its estimates on historical experience and on various other assumptions that are believed to be reasonable, the results of which form the basis for making judgments about the carrying values of assets and liabilities. Actual results may differ from these estimates under different assumptions or conditions. Changes in estimates are reflected in reported results in the period in which they become known.

Consolidation

The Company’s consolidated financial statements reflect its financial statements and those of its subsidiaries in which the Company holds a controlling financial interest. For consolidated entities in which the Company owns or is exposed to less than 100% of the economics, the Company records net income (loss) attributable to noncontrolling interests in its consolidated statements of income equal to the percentage of the economic or ownership interest retained in such entities by the respective noncontrolling parties. Intercompany balances and transactions are eliminated in consolidation.

Summary of Significant Accounting Policies

The Company’s significant accounting policies are described in Note 1, “Description of Business and Summary of Significant Accounting Policies,” in the 2014 Annual Report on Form 10-K.

New Accounting Pronouncements

In February 2015, the Financial Accounting Standards Board (FASB) issued Accounting Standards Update (ASU) 2015-02, “Amendments to the Consolidation Analysis,” which amends existing consolidation requirements. The guidance affects reporting entities that are required to evaluate whether they should consolidate certain legal entities. Specifically, the guidance amends (i) the identification of variable interests (fees paid to a decision maker or service provider), (ii) the variable interest entity characteristics for a limited partnership or similar entity and (iii) the primary beneficiary determination. The ASU is effective for fiscal years beginning after December 15, 2015, and interim periods within those fiscal years. Early adoption is permitted. The adoption of this standard is not expected to have a significant impact on the Company’s financial position or results of operations.

In April 2015, the FASB issued ASU 2015-03 “Simplifying the Presentation of Debt Issuance Costs,” which requires debt issuance costs to be presented in the balance sheet as a direct deduction from the carrying value of the associated debt liability, consistent with the presentation of debt discounts or premiums. The ASU is effective for fiscal years beginning after December 15, 2015, and interim periods within those fiscal years. Early adoption is permitted for financial statements that have not been previously issued. The adoption of this standard is not expected to have a significant impact on the Company’s financial position or results of operations.

In April 2015, FASB issued ASU 2015-04 “Practical Expedient for the Measurement Date of an Employer’s Defined Benefit Obligation and Plan Assets” to provide a practical expedient related to the measurement date of the defined benefit plan assets and obligations. The practical expedient allows employers with fiscal year-end dates that do not coincide with a calendar month end to measure pension and post-retirement benefit plan assets and obligations as of the calendar month-end date closest to the fiscal year end. The standard requires entities which elect the practical expedient to adjust the measurement of benefit plan assets and obligations for contributions or significant events between the month-end measurement date and the entity fiscal year end. The ASU is effective for fiscal years beginning after December 15, 2015, and interim periods within those fiscal years. Early adoption is permitted. The Company is still evaluating the impact the election of the practical expedient would have on its consolidated financial statements and related disclosures.

In May 2014, the FASB issued ASU 2014-09, “Revenue from Contracts with Customers.” The standard requires an entity to recognize the amount of revenue to which it expects to be entitled for the transfer of promised goods or services to customers. The standard will replace most existing revenue recognition guidance in U.S. GAAP when it becomes effective and permits the use of either the retrospective or cumulative effect transition method. The ASU is effective for annual and interim periods beginning after December 15, 2016. On April 1, 2015, the FASB voted on to propose a deferral of the effective date of the ASU by one year, but to permit entities to adopt one year earlier if they choose. The proposed deferral is not a final decision and is still subject to the FASB’s due process requirement, which includes a period for public comments. The Company has not yet selected a transition method and is evaluating the impact the adoption will have on its consolidated financial statements and related disclosures.