Amount of realized and unrealized gain (loss) of derivative instruments not designated or qualifying as hedging instruments.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4CC
-URI http://asc.fasb.org/extlink&oid=121590274&loc=SL109998890-113959

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4C
-Subparagraph (e)
-URI http://asc.fasb.org/extlink&oid=121590274&loc=SL5624171-113959

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- Definition

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

+ References

No definition available.

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- Definition

Amount of transfers of financial instrument classified as a liability 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=117815213&loc=d3e19207-110258

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- Definition

Amount of issuances of financial instrument classified as a liability 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
-Subparagraph (c)(2)
-URI http://asc.fasb.org/extlink&oid=117815213&loc=d3e19207-110258

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- Definition

Fair value of financial instrument classified as a liability 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
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=117815213&loc=d3e19207-110258

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FAIR VALUE MEASUREMENTS, Change in Level 3 Fair Value of Warrant Liabilities (FY) (Details) - USD ($)	3 Months Ended			6 Months Ended
	Mar. 31, 2021	Sep. 30, 2020	Sep. 30, 2020	Dec. 31, 2020
Unobservable Input Reconciliation [Roll Forward]
Change in fair value of warrant liabilities	$ 5,068,000	$ 181,000	$ 181,000	$ (7,240,000)
Warrant Liabilities [Member]
Unobservable Input Reconciliation [Roll Forward]
Level 3 - Beginning balance	0	0		0
Initial measurement on September 17, 2020				16,290,000
Change in fair value of warrant liabilities				7,240,000
Level 3 - Ending balance				0
Warrant Liabilities [Member] \| Level 2 [Member]
Unobservable Input Reconciliation [Roll Forward]
Transfer from Level 3				(8,580,000)
Warrant Liabilities [Member] \| Level 1 [Member]
Unobservable Input Reconciliation [Roll Forward]
Transfer from Level 3				(14,950,000)
Warrant Liabilities [Member] \| Private Placement Warrants [Member]
Unobservable Input Reconciliation [Roll Forward]
Level 3 - Beginning balance	0	0		0
Initial measurement on September 17, 2020				5,940,000
Change in fair value of warrant liabilities				2,640,000
Level 3 - Ending balance				0
Warrant Liabilities [Member] \| Private Placement Warrants [Member] \| Level 2 [Member]
Unobservable Input Reconciliation [Roll Forward]
Transfer from Level 3				(8,580,000)
Warrant Liabilities [Member] \| Private Placement Warrants [Member] \| Level 1 [Member]
Unobservable Input Reconciliation [Roll Forward]
Transfer from Level 3				0
Warrant Liabilities [Member] \| Public Warrants [Member]
Unobservable Input Reconciliation [Roll Forward]
Level 3 - Beginning balance	$ 0	$ 0		0
Initial measurement on September 17, 2020				10,350,000
Change in fair value of warrant liabilities				4,600,000
Level 3 - Ending balance				0
Warrant Liabilities [Member] \| Public Warrants [Member] \| Level 2 [Member]
Unobservable Input Reconciliation [Roll Forward]
Transfer from Level 3				0
Warrant Liabilities [Member] \| Public Warrants [Member] \| Level 1 [Member]
Unobservable Input Reconciliation [Roll Forward]
Transfer from Level 3				$ (14,950,000)