Concentrations of Credit Risk	3 Months Ended
Mar. 31, 2020
Risks and Uncertainties [Abstract]
Concentrations of Credit Risk	Concentrations of Credit Risk Financial instruments could potentially expose us to concentrations of credit risk, including unsecured receivables from the Exchange. A large majority of our revenue and receivables are from the Exchange and its affiliates. See also Note 1, "Nature of Operations". Net management fee amounts and other reimbursements due from the Exchange and its affiliates were $482.2 million and $468.6 million at March 31, 2020 and December 31, 2019, respectively. Given the financial strength of the Exchange and historical experience of no credit losses, we previously did not record a credit loss allowance to these receivables. Upon adoption of ASU 2016-13, we recorded an allowance for current expected credit losses of $0.6 million related to the receivables from the Exchange and affiliates. See also Note 2, "Significant Accounting Policies". There was no change to this allowance for the three months ended March 31, 2020.

Concentrations of Credit Risk

3 Months Ended

Mar. 31, 2020

Financial instruments could potentially expose us to concentrations of credit risk, including unsecured receivables from the Exchange. A large majority of our revenue and receivables are from the Exchange and its affiliates. See also Note 1, "Nature of Operations". Net management fee amounts and other reimbursements due from the Exchange and its affiliates were $482.2 million and $468.6 million at March 31, 2020 and December 31, 2019, respectively. Given the financial strength of the Exchange and historical experience of no credit losses, we previously did not record a credit loss allowance to these receivables. Upon adoption of ASU 2016-13, we recorded an allowance for current expected credit losses of $0.6 million related to the receivables from the Exchange and affiliates. See also Note 2, "Significant Accounting Policies". There was no change to this allowance for the three months ended March 31, 2020.