Note 11 - Fair Value of Financial Instruments - Carrying Amounts and Estimated Fair Values of Selected Financial Instruments (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Securities held-to-maturity, amortized cost	$ 60,040	$ 32,018
Securities available for sale, fair value	825,475	822,655
Interest Rate Swap [Member]
Interest Rate Swaps, Net Amount	156	1,001
Interest rate swaps	(82)	2,239
Collateralized Mortgage Backed Securities [Member]
Securities held-to-maturity, amortized cost	7,939	7,953
Securities available for sale, fair value	579,010	557,953
Other Debt Obligations [Member]
Securities held-to-maturity, amortized cost	52,101	24,065
Securities available for sale, fair value	246,465	264,702
Reported Value Measurement [Member]
Cash and due from banks	86,989	118,561
Loans	5,765,763	5,551,484
FHLB-NY stock	65,280	57,282
Accrued interest receivable	26,566	25,485
Deposits	4,974,312	4,960,784
Borrowings	1,422,440	1,250,843
Accrued interest payable	8,284	5,890
Reported Value Measurement [Member] \| Interest Rate Swap [Member]
Interest Rate Swaps, Net Amount	156	15,961
Interest rate swaps	30,988	2,239
Reported Value Measurement [Member] \| Collateralized Mortgage Backed Securities [Member]
Securities held-to-maturity, amortized cost	7,939	7,953
Securities available for sale, fair value	579,010	557,953
Reported Value Measurement [Member] \| Other Debt Obligations [Member]
Securities held-to-maturity, amortized cost	52,101	24,065
Securities available for sale, fair value	246,465	264,702
Estimate of Fair Value Measurement [Member]
Cash and due from banks	86,989	118,561
Loans	5,809,209	5,496,266
FHLB-NY stock	65,280	57,282
Accrued interest receivable	26,566	25,485
Deposits	4,979,324	4,955,077
Borrowings	1,628,483	1,241,745
Accrued interest payable	8,284	5,890
Estimate of Fair Value Measurement [Member] \| Interest Rate Swap [Member]
Interest Rate Swaps, Net Amount	156	15,961
Interest rate swaps	30,988	2,239
Estimate of Fair Value Measurement [Member] \| Collateralized Mortgage Backed Securities [Member]
Securities held-to-maturity, amortized cost	8,372	7,366
Securities available for sale, fair value	579,010	557,953
Estimate of Fair Value Measurement [Member] \| Other Debt Obligations [Member]
Securities held-to-maturity, amortized cost	55,498	22,508
Securities available for sale, fair value	246,465	264,702
Estimate of Fair Value Measurement [Member] \| Fair Value, Inputs, Level 1 [Member]
Cash and due from banks	86,989	118,561
Loans	0	0
FHLB-NY stock	0	0
Accrued interest receivable	12	54
Deposits	3,467,936	3,397,474
Borrowings	0	0
Accrued interest payable	0	0
Estimate of Fair Value Measurement [Member] \| Fair Value, Inputs, Level 1 [Member] \| Interest Rate Swap [Member]
Interest Rate Swaps, Net Amount	0	0
Interest rate swaps	0	0
Estimate of Fair Value Measurement [Member] \| Fair Value, Inputs, Level 1 [Member] \| Collateralized Mortgage Backed Securities [Member]
Securities held-to-maturity, amortized cost	0	0
Securities available for sale, fair value	0	0
Estimate of Fair Value Measurement [Member] \| Fair Value, Inputs, Level 1 [Member] \| Other Debt Obligations [Member]
Securities held-to-maturity, amortized cost	0	0
Securities available for sale, fair value	12,206	11,586
Estimate of Fair Value Measurement [Member] \| Fair Value, Inputs, Level 2 [Member]
Cash and due from banks	0	0
Loans	0	0
FHLB-NY stock	65,280	57,282
Accrued interest receivable	2,767	2,756
Deposits	1,511,388	1,557,603
Borrowings	1,584,573	1,199,896
Accrued interest payable	8,284	5,890
Estimate of Fair Value Measurement [Member] \| Fair Value, Inputs, Level 2 [Member] \| Interest Rate Swap [Member]
Interest Rate Swaps, Net Amount	156	15,961
Interest rate swaps	30,988	2,239
Estimate of Fair Value Measurement [Member] \| Fair Value, Inputs, Level 2 [Member] \| Collateralized Mortgage Backed Securities [Member]
Securities held-to-maturity, amortized cost	8,372	7,366
Securities available for sale, fair value	579,010	557,953
Estimate of Fair Value Measurement [Member] \| Fair Value, Inputs, Level 2 [Member] \| Other Debt Obligations [Member]
Securities held-to-maturity, amortized cost	0	0
Securities available for sale, fair value	232,941	251,860
Estimate of Fair Value Measurement [Member] \| Fair Value, Inputs, Level 3 [Member]
Cash and due from banks	0	0
Loans	5,809,209	5,496,266
FHLB-NY stock	0	0
Accrued interest receivable	23,787	22,675
Deposits	0	0
Borrowings	43,910	41,849
Accrued interest payable	0	0
Estimate of Fair Value Measurement [Member] \| Fair Value, Inputs, Level 3 [Member] \| Interest Rate Swap [Member]
Interest Rate Swaps, Net Amount	0	0
Interest rate swaps	0	0
Estimate of Fair Value Measurement [Member] \| Fair Value, Inputs, Level 3 [Member] \| Collateralized Mortgage Backed Securities [Member]
Securities held-to-maturity, amortized cost	0	0
Securities available for sale, fair value	0	0
Estimate of Fair Value Measurement [Member] \| Fair Value, Inputs, Level 3 [Member] \| Other Debt Obligations [Member]
Securities held-to-maturity, amortized cost	55,498	22,508
Securities available for sale, fair value	$ 1,318	$ 1,256

Fair value portion of accrued interest payable.

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Fair value portion of accrued interest receivable.

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Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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Fair value portion of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates.

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Fair value portion of debt instrument payable, including, but not limited to, notes payable and loans payable.

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Fair value portion of deposit liabilities held by the entity, including, but not limited to, foreign and domestic, interest and noninterest bearing, demand deposits, saving deposits, negotiable orders of withdrawal (NOW) and time deposits.

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Fair value, after the effects of master netting arrangements, of a financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes assets not subject to a master netting arrangement and not elected to be offset.

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Fair value, after the effects of master netting arrangements, of a financial liability or contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes liabilities not subject to a master netting arrangement and not elected to be offset.

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Amount of investment in debt security measured at amortized cost (held-to-maturity).

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Fair value portion of investments in Federal Home Loan Bank (FHLBank) stock.

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Fair value portion of loan receivable, including, but not limited to, mortgage loans held for investment, finance receivables held for investment, policy loans on insurance contracts.

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