CONDENSED STATEMENTS OF CHANGES IN STOCKHOLDERS' EQUITY (DEFICIT) (Unaudited) (Parenthetical) (Q3)	Jun. 24, 2019 shares
Initial Public Offering [Member]
Stockholders' Equity
Units issued (in shares)	25,000,000
Private Placement Warrant [Member]
Stockholders' Equity
Warrants issued (in shares)	6,954,500

Number of new units issued during the period. Each unit consists of one share of Class A common stock and one redeemable warrant.

No definition available.

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Namespace Prefix:	smmc_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration