Document And Entity Information - shares	6 Months Ended
	Sep. 30, 2017	Oct. 20, 2017
Document Information [Line Items]
Entity Registrant Name	Seneca Foods Corporation
Entity Central Index Key	0000088948
Trading Symbol	senea
Current Fiscal Year End Date	--03-31
Entity Filer Category	Accelerated Filer
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Well-known Seasoned Issuer	No
Document Type	10-Q/A
Document Period End Date	Sep. 30, 2017
Document Fiscal Year Focus	2018
Document Fiscal Period Focus	Q2
Amendment Flag	true
Amendment Description	Restatement of Consolidated Condensed Financial Statements Seneca Foods Corporation ("the "Company") is filing this Amendment No. 1 ("Form 10-Q/A") to our Form 10-Q for the quarterly period ended September 30, 2017, which was originally filed on October 26, 2017 ("Original Filing"), to restate our Consolidated Condensed Financial Statements and the related notes for the three and six months ended September 30, 2017 and October 1, 2016, including the financial information included in Management's Discussion and Analysis of Financial Condition and Results of Operations. We are also providing an update in our disclosures regarding the material weakness in Item 4 of this amended Form 10-Q/A. As previously disclosed, on June 28, 2018, the Company’s Audit Committee, in consultation with the Board of Directors, concluded that the Company’s previously issued financial statements for the three and six months ended September 30, 2017 and October 1, 2016 (among other periods, see below) could no longer be relied upon. This decision was reached after discussions with the Company’s senior management and outside advisers. In reviewing the accounting for certain transactions related to the Company’s contract packing agreement, the Green Giant contract, our management identified a deficiency in the effectiveness of a control intended to properly document and review relevant facts in connection with our revenue recognition policy with respect to bill and hold transactions. The Company has determined that (1) the audited consolidated financial statements as of and for the years ended March 31, 2014, 2015, 2016 and 2017 and the independent registered public accounting firm’s reports thereon and (2) the unaudited condensed consolidated financial statements as of and for each of the interim periods within the years ended March 31, 2017 and 2018 should be restated to correct inadvertent errors in the application of generally accepted accounting principles dealing with complex and technical accounting issues relating to “bill and hold” revenue recognition. To correct this misstatement and to address matters related to the foregoing with respect to our disclosure controls and procedures and our internal control over financial reporting, we have restated our Consolidated Condensed Financial Statements and the related notes for the three and six months ended September 30, 2017, including the financial information included in Management's Discussion and Analysis of Financial Condition and Results of Operations. See Note 2 - Restatement of Consolidated Condensed Financial Statements, which is included in the "Financial Statements" in Item 1 of this amended Form 10-Q/A for more detail. Amended Items in this Form 10Q/A The following items in the Original Filing have been amended: Part I, Item 1. Financial Statements Part I, Item 2. Management's Discussion and Analysis of Financial Condition and Results of Operations Part I, Item 4. Controls and Procedures Part II, Item 6. Exhibits We are also filing currently dated certifications from our Chief Executive Officer and Chief Financial Officer as Exhibits 31.1, 31.2, 32, as well as various exhibits related to XBRL. This amended Form 10-Q/A does not reflect events occurring after the Original Filing on October 26, 2017, or modify or update those disclosures affected by subsequent events, except for the effects of the restatement. Disclosures not affected by the restatement are unchanged and reflect the disclosures made at the time of Original Filing.
Common Class A [Member]
Document Information [Line Items]
Entity Common Stock, Shares Outstanding (in shares)		7,875,188
Common Class B [Member]
Document Information [Line Items]
Entity Common Stock, Shares Outstanding (in shares)		1,884,439