Note 8 - Deposits - Interest Expense on Deposits (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Certificate of deposit accounts	$ 20,579	$ 20,536	$ 20,943
Savings accounts	1,808	1,219	1,151
Money market accounts	8,151	3,592	1,551
NOW accounts	9,640	7,891	6,593
Total due to depositors	40,178	33,238	30,238
Mortgagors' escrow deposits	141	112	98
Total interest expense on deposits	$ 40,319	$ 33,350	$ 30,336

The aggregate interest expense incurred on mortgagors' escrow deposits.

No definition available.

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Period Type:	duration

- Definition

The aggregate interest expense incurred on mortgagors' escrow deposits.

+ References

No definition available.

+ Details

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Namespace Prefix:	ffic_
Data Type:	xbrli:monetaryItemType
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- Definition

Aggregate amount of interest expense on all deposits.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 225
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-04.6)
-URI http://asc.fasb.org/extlink&oid=6879574&loc=d3e536633-122882

+ Details

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- Definition

Interest expense incurred on all money market deposits.

+ References

+ Details

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Balance Type:	debit
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- Definition

Interest expense incurred on the amount of Negotiable Order of Withdrawal (NOW). Interest-bearing transaction account that combines the payable on demand feature of checks and investment feature of savings accounts. A NOW account is functionally an interest paying checking account.

+ References

+ Details

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- Definition

Interest expense incurred on all savings account deposits.

+ References

+ Details

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Balance Type:	debit
Period Type:	duration

- Definition

The aggregate interest expense incurred on time deposits, including certificates of deposits, in domestic offices.

+ References

+ Details

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