Document And Entity Information - shares	6 Months Ended
	Jun. 30, 2023	Jul. 31, 2023
Cover [Abstract]
Document Type	10-Q/A
Document Quarterly Report	true
Document Transition Report	false
Document Period End Date	Jun. 30, 2023
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2023
Entity File Number	001-33013
Entity Registrant Name	FLUSHING FINANCIAL CORPORATION
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	11-3209278
Entity Address, Address Line One	220 RXR Plaza
Entity Address, City or Town	Uniondale
Entity Address, State or Province	NY
Entity Address, Postal Zip Code	11556
City Area Code	(718)
Local Phone Number	961-5400
Title of 12(b) Security	Common Stock, $0.01 par value
Trading Symbol	FFIC
Security Exchange Name	NASDAQ
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding (in shares)		28,963,936
Entity Central Index Key	0000923139
Document Fiscal Period Focus	Q2
Amendment Flag	true
Amendment Description	This amended and restated Quarterly Report on Form 10-Q/A (this "Quarterly Report") amends and restates in its entirety the Quarterly Report on Form 10-Q for the three and six months ended June 30, 2023, filed by Flushing Financial Corporation (the "Company") with the Securities and Exchange Commission (the "SEC") on August 9, 2023.As disclosed in the Company's Current Report on Form 8-K filed with the SEC on January 26, 2024, management and the Audit Committee of the Board of Directors of the Company determined that the Company's consolidated financial statements for the three- and six-month periods ended June 30, 2023, required restatement to correct the accounting treatment of employee retention credits (the "ERCs") and disclosures, which ERCs were incorrectly recognized as income during such periods. The change impacted net income by an increase of $0.1 million and a decrease of $1.1 million, respectively, for the three- and six-month periods ended June 30, 2023. In the course of preparing the Company's consolidated financial statements for the fiscal year ended December 31, 2023, the Company determined that, notwithstanding reliance on its independent tax credit advisors, it is not able to treat the ultimate realization of the ERCs as "probable" under U.S. generally accepted accounting practices, therefore, requiring the restatement of the Company's previously issued consolidated financial statements for the referenced periods and amendments to the Company's related previously filed quarterly reports on Form 10-Q during such year. Although the Company had engaged an independent national tax credit advisory firm that had advised the Company that it qualified for the ERCs as previously reported, the Company determined that it could no longer rely on such advice. In connection with its evaluation of the restatements described above, management of the Company has concluded that a material weakness in the Company's internal control over financial reporting existed as of June 30, 2023. Specifically, the Company did not maintain effective controls over the probability assessment associated with the recognition of income related to the ERCs. See additional discussion included in Part I – Item 4, "Controls and Procedures" of this Quarterly Report.