Note 8 - Deposits (Details) - Interest Expense on Deposits (USD $) In Thousands, unless otherwise specified	3 Months Ended	12 Months Ended
Mar. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Interest Expense on Deposits [Abstract]
Certificate of deposit accounts	$ 22,420us-gaap_InterestExpenseTimeDeposits	$ 24,414us-gaap_InterestExpenseTimeDeposits	$ 32,983us-gaap_InterestExpenseTimeDeposits
Savings accounts	597us-gaap_InterestExpenseSavingsDeposits	515us-gaap_InterestExpenseSavingsDeposits	689us-gaap_InterestExpenseSavingsDeposits
Money market accounts	667	294	399
NOW accounts	6,227	6,777	6,275
Total due to depositors	29,911	32,000	40,346
Mortgagors' escrow deposits	133	37	36
Total interest expense on deposits	$ 30,044us-gaap_InterestExpenseDeposits	$ 32,037us-gaap_InterestExpenseDeposits	$ 40,382us-gaap_InterestExpenseDeposits	$ 30,044us-gaap_InterestExpenseDeposits	$ 32,037us-gaap_InterestExpenseDeposits	$ 40,382us-gaap_InterestExpenseDeposits

Aggregate amount of interest expense on all deposits, excluding mortgagors' escrow deposits.

No definition available.

Name:	ffic_InterestExpenseDepositsExcludingMortgagorsEscrowDeposits
Namespace Prefix:	ffic_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

The aggregate interest expense incurred on mortgagors' escrow deposits.

+ References

No definition available.

+ Details

Name:	ffic_InterestExpenseMortgagorsEscrowDeposits
Namespace Prefix:	ffic_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Details

Name:	ffic_InterestExpenseOnDepositsAbstract
Namespace Prefix:	ffic_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- 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

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 04

-Paragraph 6

-Article 9

+ Details

Name:	us-gaap_InterestExpenseDeposits
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Interest expense incurred on all money market deposits.

+ References

+ Details

Name:	us-gaap_InterestExpenseMoneyMarketDeposits
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- 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

Name:	us-gaap_InterestExpenseNegotiableOrderOfWithdrawalNOWDeposits
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Interest expense incurred on all savings account deposits.

+ References

+ Details

Name:	us-gaap_InterestExpenseSavingsDeposits
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

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

+ References

+ Details

Name:	us-gaap_InterestExpenseTimeDeposits
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration