Nature of Operations and Summary of Significant Accounting Policies	3 Months Ended
Jun. 30, 2012
Notes To Financial Statements [Abstract]
Nature of Operations and Summary of Significant Accounting Policies	Nature of Operations and Summary of Significant Accounting Policies Nature of Operations STERIS Corporation, an Ohio corporation, develops, manufactures and markets infection prevention, contamination control, microbial reduction, and surgical and critical care support products and services for healthcare, pharmaceutical, scientific, research, industrial, and governmental Customers throughout the world. As used in this Quarterly Report, STERIS Corporation and its subsidiaries together are called “STERIS,” the “Company,” “we,” “us,” or “our,” unless otherwise noted. We operate in three reportable business segments: Healthcare, Life Sciences, and STERIS Isomedix Services (“Isomedix”). We describe our business segments in note 10 to our consolidated financial statements titled, “Business Segment Information.” Our fiscal year ends on March 31. References in this Quarterly Report to a particular “year” or “year-end” mean our fiscal year. The significant accounting policies applied in preparing the accompanying consolidated financial statements of the Company are summarized below: Interim Financial Statements We prepared the accompanying unaudited consolidated financial statements of the Company according to accounting principles generally accepted in the United States (“U.S. GAAP”) for interim financial information and the instructions to the Quarterly Report on Form 10-Q and Rule 10-01 of Regulation S-X. This means that they do not include all of the information and footnotes required by U.S. GAAP for complete financial statements. Our unaudited interim consolidated financial statements contain all material adjustments (including normal recurring accruals and adjustments) management believes are necessary to fairly state our financial condition, results of operations, and cash flows for the periods presented. These interim consolidated financial statements should be read together with the consolidated financial statements and related notes included in our Annual Report on Form 10-K for the year ended March 31, 2012 dated May 29, 2012. The Consolidated Balance Sheet at March 31, 2012 was derived from the audited consolidated financial statements at that date, but does not include all of the information and footnotes required by U.S. GAAP for complete financial statements. Principles of Consolidation We use the consolidation method to report our investment in our subsidiaries. Therefore, the accompanying consolidated financial statements include the accounts of the Company and its wholly-owned and majority-owned subsidiaries. We eliminate inter-company accounts and transactions when we consolidate these accounts. Use of Estimates We make certain estimates and assumptions when preparing financial statements according to U.S. GAAP that affect the reported amounts of assets and liabilities at the financial statement dates and the reported amounts of revenues and expenses during the periods presented. These estimates and assumptions involve judgments with respect to many factors that are difficult to predict and are beyond our control. Actual results could be materially different from these estimates. We revise the estimates and assumptions as new information becomes available. This means that operating results for the three month period ended June 30, 2012 are not necessarily indicative of results that may be expected for future quarters or for the full fiscal year ending March 31, 2013. Recently Adopted Accounting Pronouncements In June 2011, the FASB issued an accounting standard update titled "Presentation of Comprehensive Income," amending Accounting Standards Codification ASC Topic 220, "Comprehensive Income." This guidance requires that all non-owner changes in stockholders’ equity be presented either in a single continuous statement of comprehensive income or in two separate but consecutive statements. This guidance became effective retrospectively for the interim periods and annual periods beginning after December 15, 2011; however, the FASB agreed to an indefinite deferral of the reclassification requirement as defined in accounting standard update titled "Deferral of the Effective Date for Amendments to the Presentation of Reclassifications of Items Out of Accumulated Other Comprehensive Income," issued in December 2011. The adoption of this standard did not have an impact on our consolidated financial position, results of operations or cash flows. Significant Accounting Policies A detailed description of our significant and critical accounting policies, estimates, and assumptions is included in our consolidated financial statements included in our Annual Report on Form 10-K for the year ended March 31, 2012 dated May 29, 2012. Our significant and critical accounting policies, estimates, and assumptions have not changed materially from March 31, 2012.

Nature of Operations and Summary of Significant Accounting Policies

Nature of Operations

STERIS Corporation, an Ohio corporation, develops, manufactures and markets infection prevention, contamination control, microbial reduction, and surgical and critical care support products and services for healthcare, pharmaceutical, scientific, research, industrial, and governmental Customers throughout the world. As used in this Quarterly Report, STERIS Corporation and its subsidiaries together are called “STERIS,” the “Company,” “we,” “us,” or “our,” unless otherwise noted.

We operate in three reportable business segments: Healthcare, Life Sciences, and STERIS Isomedix Services (“Isomedix”). We describe our business segments in note 10 to our consolidated financial statements titled, “Business Segment Information.” Our fiscal year ends on March 31. References in this Quarterly Report to a particular “year” or “year-end” mean our fiscal year. The significant accounting policies applied in preparing the accompanying consolidated financial statements of the Company are summarized below:

Interim Financial Statements

We prepared the accompanying unaudited consolidated financial statements of the Company according to accounting principles generally accepted in the United States (“U.S. GAAP”) for interim financial information and the instructions to the Quarterly Report on Form 10-Q and Rule 10-01 of Regulation S-X. This means that they do not include all of the information and footnotes required by U.S. GAAP for complete financial statements. Our unaudited interim consolidated financial statements contain all material adjustments (including normal recurring accruals and adjustments) management believes are necessary to fairly state our financial condition, results of operations, and cash flows for the periods presented.

These interim consolidated financial statements should be read together with the consolidated financial statements and related notes included in our Annual Report on Form 10-K for the year ended March 31, 2012 dated May 29, 2012. The Consolidated Balance Sheet at March 31, 2012 was derived from the audited consolidated financial statements at that date, but does not include all of the information and footnotes required by U.S. GAAP for complete financial statements.

Principles of Consolidation

We use the consolidation method to report our investment in our subsidiaries. Therefore, the accompanying consolidated financial statements include the accounts of the Company and its wholly-owned and majority-owned subsidiaries. We eliminate inter-company accounts and transactions when we consolidate these accounts.

Use of Estimates

We make certain estimates and assumptions when preparing financial statements according to U.S. GAAP that affect the reported amounts of assets and liabilities at the financial statement dates and the reported amounts of revenues and expenses during the periods presented. These estimates and assumptions involve judgments with respect to many factors that are difficult to predict and are beyond our control. Actual results could be materially different from these estimates. We revise the estimates and assumptions as new information becomes available. This means that operating results for the three month period ended June 30, 2012 are not necessarily indicative of results that may be expected for future quarters or for the full fiscal year ending March 31, 2013.

Recently Adopted Accounting Pronouncements

In June 2011, the FASB issued an accounting standard update titled "Presentation of Comprehensive Income," amending Accounting Standards Codification ASC Topic 220, "Comprehensive Income." This guidance requires that all non-owner changes in stockholders’ equity be presented either in a single continuous statement of comprehensive income or in two separate but consecutive statements. This guidance became effective retrospectively for the interim periods and annual periods beginning after December 15, 2011; however, the FASB agreed to an indefinite deferral of the reclassification requirement as defined in accounting standard update titled "Deferral of the Effective Date for Amendments to the Presentation of Reclassifications of Items Out of Accumulated Other Comprehensive Income," issued in December 2011. The adoption of this standard did not have an impact on our consolidated financial position, results of operations or cash flows.

Significant Accounting Policies

A detailed description of our significant and critical accounting policies, estimates, and assumptions is included in our consolidated financial statements included in our Annual Report on Form 10-K for the year ended March 31, 2012 dated May 29, 2012. Our significant and critical accounting policies, estimates, and assumptions have not changed materially from March 31, 2012.