Document And Entity Information - shares	6 Months Ended
	Jun. 30, 2019	Jul. 31, 2019
Document Information [Line Items]
Entity Central Index Key	0000923139
Entity Shell Company	false
Entity Registrant Name	Flushing Financial Corporation
Amendment Flag	false
Current Fiscal Year End Date	--12-31
Document Fiscal Period Focus	Q2
Document Fiscal Year Focus	2019
Entity Small Business	false
Entity Emerging Growth Company	false
Document Quarterly Report	true
Document Transition Report	false
Document Type	10-Q
Document Period End Date	Jun. 30, 2019
Entity File Number	001-33013
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
Trading Symbol	FFIC
Security Exchange Name	NASDAQ
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		28,187,922