Interest Income And Interest Expense (Details) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2018	Mar. 31, 2017
Interest Income Expense Net [Abstract]
Bank loans, net	$ 63,635	$ 44,771
Investment securities	54,903	41,666
Margin balances	10,950	8,182
Inventory	4,929	4,236
Other	3,317	2,098
Total interest income	137,734	100,953
Senior notes	11,118	8,140
Bank deposits	8,130	1,768
Federal Home Loan Bank advances	3,252	1,719
Other	3,953	4,269
Total interest expense	$ 26,453	$ 15,896

Interest income from inventory.

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Margin balances.

+ References

No definition available.

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- Definition

Other interest and dividend income expense net.

+ References

No definition available.

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- Definition

Amount of operating dividend and interest income, including amortization and accretion of premiums and discounts, on available-for-sale securities.

+ 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 210.9-04.2)
-URI http://asc.fasb.org/extlink&oid=6879574&loc=d3e536633-122882

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 35
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=82895926&loc=d3e24721-111560

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The aggregate interest and fee income generated by: (1) loans the Entity has positive intent and ability to hold for the foreseeable future, or until maturity or payoff, including commercial and consumer loans, whether domestic or foreign, which may consist of: (a) industrial and agricultural; (b) real estate; and (c) real estate construction loans; (d) trade financing; (e) lease financing; (f) home equity lines-of-credit; (g) automobile and other vehicle loans; and (h) credit card and other revolving-type loans and (2) loans and leases held-for-sale which may include mortgage loans, direct financing, and sales-type leases.

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- Definition

Amount of the cost of borrowed funds accounted for as interest expense.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 20
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6450988&loc=d3e26243-108391

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-Publisher FASB
-Name Accounting Standards Codification
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-SubTopic 30
-Section 45
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-Name Accounting Standards Codification
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-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-04.9)
-URI http://asc.fasb.org/extlink&oid=6879574&loc=d3e536633-122882

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Amount of the cost of borrowed funds accounted for as interest expense for debt.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 225
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03.8)
-URI http://asc.fasb.org/extlink&oid=63488584&loc=d3e20235-122688

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The aggregate interest expense incurred on all domestic deposits.

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Interest expense incurred during the reporting period on short-term borrowings associated with Federal Home Loan Bank and Federal Reserve Bank advances.

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No definition available.

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- Definition

Amount of interest expense classified as other.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4D
-URI http://asc.fasb.org/extlink&oid=84234895&loc=SL5624177-113959

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Amount of operating interest income, including, but not limited to, amortization and accretion of premiums and discounts on securities.

+ References

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-Publisher FASB
-Name Accounting Standards Codification
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-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03.1(e))
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