Investments in Affiliates and Related Transactions	12 Months Ended
Investments in Affiliates and Related Transactions	Dec. 31, 2020
Equity Method Investments and Joint Ventures [Abstract]
Investments in Affiliates and Related Transactions	Investments in Affiliates and Related Transactions Sequential Technology International, LLC In connection with the divestiture of the exception handling business of the Company in 2017, Synchronoss entered into a three-year Cloud Telephony and Support services agreement (“CTS Agreement”) to grant Sequential Technology International, LLC (“STIN”) access to certain Synchronoss software and private branch exchange systems to facilitate exception handling operations required to support STIN customers. The CTS agreement expired in the first quarter of 2020. At the time of the expiration, the Company entered into an Asset Purchase Agreement with STIN. As part of the agreement, the Company received $1.6 million in exchange for certain hardware and system assets for the cloud telephony and remaining support service business. During the second quarter of 2020, the Company entered into an agreement with STIN and AP Capital Holdings II, LLC (“APC”) to divest its remaining equity interest in STIN as well as settle its paid-in-kind purchase money note (“PIK note”) and certain amounts due as of December 31, 2019 in consideration for a $9.0 million secured promissory note (the “Note”), which includes contingent consideration of up to $16.0 million. The Note has an 8% interest rate and a 3-year stated term. As part of the arrangement, APC acquired a majority stake of STIN. Additionally, in the event of a Sale of STIN by APC and STIN at a future date, the Company shall receive 5% of such sale proceeds, after reducing the sale proceeds by any outstanding amounts of the above Note, including any earned contingent consideration. The Company determined the fair value of the Note as of the transaction date to be approximately $4.8 million. The Company determined the fair value of the Note using a discounted cash flow analysis, which discounts the expected future cash flows of the asset to determine its fair value. The fair value measurement is based on significant inputs not observable in the market and thus represents a Level 3 measurement. The Note has been reflected in Loan Receivable on the Consolidated balance sheet. No gain or loss was recognized as a result of the transaction. As of December 31, 2020, the Company reassessed the fair value of the note and there were no material changes. For the year ended December 31, 2020 and 2019, the Company recognized nil and $(6.9) million, respectively, in revenue related to Cloud Telephony and Support services, and nil and nil, respectively, in revenue related to all other services. In 2019, changes to the STIN business led the Company to conclude that its collection of certain STIN receivables was no longer probable. In accordance with ASC 842, the portion of revenue that is no longer deemed collectible is reversed in the current period against revenue. Accordingly, the Company determined a contingency reserve was required, which included a reduction of revenue in the amount $26.0 million in the third quarter of 2019. The impacts of this change are reflected in the STIN affiliate revenue and accounts receivable. The STIN affiliate accounts receivable balances in the Consolidated Balance Sheet as of December 31, 2020 and December 31, 2019, were nil and $8.1 million, respectively. These amounts principally included revenues generated from the Cloud and Telephony Support Services agreement and pass-through of vendor expenses incurred during the transition and assignment of vendor contracts.