Subsequent Event	9 Months Ended
Sep. 30, 2021
Subsequent Events [Abstract]
Subsequent Event	Subsequent Event Westchester Capital ManagementOn October 1, 2021, the Company completed its previously announced acquisition of Westchester Capital Management ("Westchester"). The initial purchase price payment of $135.0 million was made at closing and an additional $20.0 million payment is due near year end, subject to retention of revenue levels, which is expected. Due to the limited time since the closing, the related acquisition accounting is incomplete at this time.

The entire disclosure for significant events or transactions that occurred after the balance sheet date through the date the financial statements were issued or the date the financial statements were available to be issued. Examples include: the sale of a capital stock issue, purchase of a business, settlement of litigation, catastrophic loss, significant foreign exchange rate changes, loans to insiders or affiliates, and transactions not in the ordinary course of business.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 855
-URI http://asc.fasb.org/topic&trid=2122774

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 855
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=6842918&loc=SL6314017-165662

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