Loans - Foregone on Non-accrual Loans and Loans Classified as TDR (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024
Loans
Interest income that would have been recognized had the loans performed in accordance with their original terms	$ 877	$ 900	$ 2,660	$ 2,246
Less: Interest income included in the results of operations	(410)	(5)	(593)	(10)
Total foregone interest	$ 467	$ 895	$ 2,067	$ 2,236

The gross interest income that would have been recorded in the period on troubled debt restructurings and nonaccrual loans, if the loans had been current in accordance with their original terms and had been outstanding throughout the period or since origination, if held for part of the period.

No definition available.

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Namespace Prefix:	ffic_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration