Fair Value Measurement and Fair Value of Financial Instruments (Reconciliation of Assets and Liabilities Measured on Recurring Basis) (Details) - Equity contracts - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Lending fees
Reconciliation of the beginning and ending balances for warrants issued by private companies measured at fair value on a recurring basis using significant unobservable inputs (Level 3)
Total unrealized (losses) gains for the period included in earnings	$ (27)	$ 8,000	$ (29)	$ 8,300
Fair Value, Measurements, Recurring \| Significant Unobservable Inputs (Level 3)
Reconciliation of the beginning and ending balances for warrants issued by private companies measured at fair value on a recurring basis using significant unobservable inputs (Level 3)
Beginning balance	272	713	273	421
Total (losses) gains included in earnings	47	7,976	46	8,268
Settlements	(96)	0	(96)	0
Transfers out of Level 3	0	(8,373)	0	(8,373)
Ending balance	$ 223	$ 316	$ 223	$ 316

Amount of unrealized gain (loss) recognized in income from asset measured at fair value on recurring basis using unobservable input (level 3) and still held.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=123874694&loc=d3e19207-110258

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Amount of gain (loss) recognized in income from asset measured at fair value on recurring basis using unobservable input (level 3).

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(1)
-URI http://asc.fasb.org/extlink&oid=123874694&loc=d3e19207-110258

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Amount of settlement of financial instrument classified as an asset measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.

+ References

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
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-Paragraph 2
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Amount of transfers of financial instrument classified as an asset out of level 3 of the fair value hierarchy.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(3)
-URI http://asc.fasb.org/extlink&oid=123874694&loc=d3e19207-110258

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Fair value of financial instrument classified as an asset measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
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-URI http://asc.fasb.org/extlink&oid=123874694&loc=d3e19207-110258

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A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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