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Investments in Affiliates and Related Transactions (Details) - USD ($) | 3 Months Ended | 12 Months Ended
--- | --- | ---
Dec. 31, 2020 | Sep. 30, 2020 | Jun. 30, 2020 | Mar. 31, 2020 | Dec. 31, 2019 | Sep. 30, 2019 | Jun. 30, 2019 | Mar. 31, 2019 | Dec. 31, 2020 | Dec. 31, 2019 | Dec. 31, 2018 | Dec. 31, 2017
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Reduction in revenue |  | $ (69,377,000) | $ (68,636,000) | $ (76,535,000) | $ (77,122,000) | $ (90,588,000) | $ (52,210,000) | $ (77,846,000) | $ (88,105,000) | $ (291,670,000) | $ (308,749,000) | $ (325,839,000) |
Accounts receivable, net | [1] | 47,849,000 |  |  |  | 65,863,000 |  |  |  | 47,849,000 | 65,863,000 |  |
Digital |  |  |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Reduction in revenue |  |  |  |  |  |  |  |  |  | (56,082,000) | (53,802,000) |  |
Discontinued Operations, Disposed of by Sale | BPO Divestiture |  |  |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Discontinued operation after disposal, revenue |  |  |  |  |  |  |  |  |  | 0 | 0 |  |
Discontinued Operations, Disposed of by Sale | BPO Divestiture | Cloud Technology and Support |  |  |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Discontinued operation after disposal, revenue |  |  |  |  |  |  |  |  |  | 0 | (6,900,000) |  |
Sequential Technology International L L C And A P Capital Holdings I I L L C |  |  |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Other assets fair value disclosure |  |  |  | 4,800,000 |  |  |  |  |  |  |  |  |
Sequential Technology International L L C And A P Capital Holdings I I L L C | Loans Payable |  |  |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Face amount |  |  |  | 9,000,000.0 |  |  |  |  |  |  |  |  |
Contingent consideration, liability |  |  |  | $ 16,000,000.0 |  |  |  |  |  |  |  |  |
Interest rate, as a percent |  |  |  | 8.00% |  |  |  |  |  |  |  |  |
Term |  |  |  | 3 years |  |  |  |  |  |  |  |  |
Proceeds from sale, percentage |  |  |  | 5.00% |  |  |  |  |  |  |  |  |
Sequential Technology International, LLC |  |  |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Duration of services agreement |  |  |  |  |  |  |  |  |  |  |  |  | 3 years
Consideration received |  |  |  |  | $ 1,600,000 |  |  |  |  |  |  |  |
STIN |  |  |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Accounts receivable, net |  | $ 0 |  |  |  | $ 8,100,000 |  |  |  | 0 | $ 8,100,000 |  |
STIN | Digital |  |  |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Reduction in revenue |  |  |  |  |  |  | $ 26,000,000.0 |  |  | $ 26,000,000.0 |  |  |
[1] | See Note 7. Investments in Affiliates and Related Transactions for related party transactions reflected in this account.

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