The commitment amount under the debt instrument.

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The number of counterparties related to the reverse repurchase agreements.

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Percentage points added to the reference rate to compute the variable rate on the debt instrument.

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Contractual interest rate for funds borrowed, under the debt agreement.

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Fair value of collateral permitted, by contact or custom, to be sold or re-pledged.

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Amount of current borrowing capacity under the credit facility considering any current restrictions on the amount that could be borrowed (for example, borrowings may be limited by the amount of current assets), but without considering any amounts currently outstanding under the facility.

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Amount of revenue recognized from goods sold, services rendered, insurance premiums, or other activities that constitute an earning process. Includes, but is not limited to, investment and interest income before deduction of interest expense when recognized as a component of revenue, and sales and trading gain (loss).

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Amount, after the effects of master netting arrangements, of funds outstanding loaned in the form of a security resale agreement between the entity and another party for the purchase and resale of identical or substantially the same securities at a date certain for a specified price. Includes purchases of participations in pools of securities that are subject to a resale agreement, assets not subject to a master netting arrangement and not elected to be offset.

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Note 11 - Collateralized Securities Transactions (Details Textual) $ in Thousands		1 Months Ended								12 Months Ended
	Oct. 19, 2018	Dec. 31, 2020 USD ($)	Sep. 30, 2020 USD ($)	Jun. 30, 2020 USD ($)	Mar. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)	Sep. 30, 2019 USD ($)	Jun. 30, 2019 USD ($)	Mar. 31, 2019 USD ($)	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Apr. 25, 2018 USD ($)
Securities Purchased under Agreements to Resell, Total		$ 5,716,343				$ 7,500,002				$ 5,716,343	$ 7,500,002
Fair Value of Securities Received as Collateral that Can be Resold or Repledged		$ 5,885,656				$ 7,769,693				$ 5,885,656	$ 7,769,693
Number of Counterparties Related to Reverse Repurchase Agreements		38				41				38	41
Securities Sold under Agreements to Repurchase, Total		$ 5,713,212				$ 7,534,443				$ 5,713,212	$ 7,534,443
Fair Value of Securities Received as Collateral that Have Been Resold or Repledged		5,768,018				7,561,978				5,768,018	7,561,978
Revenues, Total		66,365	$ 21,856	$ 24,119	$ 17,770	16,090	$ 11,267	$ 11,169	$ 11,140	130,110	49,666	$ 49,386
Fixed Income Clearing Corporation the (FICC) [Member]
Securities Purchased under Agreements to Resell, Total		99,750				371,025				99,750	371,025
Securities Sold under Agreements to Repurchase, Total		$ 2,155,850				$ 5,138,712				$ 2,155,850	$ 5,138,712
Gestational Repo Business [Member]
Number of Counterparties Related to Reverse Repurchase Agreements		11				7				11	7
Revenues, Total										$ 33,980	$ 12,011	$ 4,624
Intraday and Overnight Lending Facility [Member]
Debt Instrument, Commitment Amount		$ 75,000								75,000
Debt Instrument, Renewal Term (Day)	364 days
Debt Instrument, Interest Rate, Stated Percentage	0.12%
Short-term Debt, Total		32,818								32,818
Interest Payable, Current		2								2
Intraday and Overnight Lending Facility [Member] \| Payable to Brokers, Dealers, and Clearing Agencies [Member]
Short Term Debt, Including Accrued Interest		$ 32,820								$ 32,820
Intraday and Overnight Lending Facility [Member] \| Base Rate [Member]
Debt Instrument, Basis Spread on Variable Rate	3.00%
Intraday and Overnight Lending Facility [Member] \| Fed Funds Effective Rate Overnight Index Swap Rate [Member]
Debt Instrument, Basis Spread on Variable Rate	0.50%
Fifth Third Financial Bank [Member]
Line of Credit Facility, Current Borrowing Capacity													$ 25,000