Related-Party Transactions	9 Months Ended
Sep. 30, 2018
Related Party Transactions [Abstract]
Related-Party Transactions	10. RELATED-PARTY TRANSACTIONS Aircraft Lease— On August 30, 2014, a related party, Moelis & Company Manager LLC ("Manager"), acquired an aircraft with funds received solely from its managing member (Mr. Moelis). The aircraft is used and operated by the Company pursuant to a dry lease with Manager which terminates on December 31, 2019. The terms of the dry lease are comparable to the market rates of leasing from an independent third party. Pursuant to this dry lease arrangement, the lessee is obligated to bear its share of the costs of operating the aircraft. For the three months ended September 30, 2018 and 2017, the Company incurred $468 and $468 in aircraft lease costs to be paid to Manager, respectively, and $1,404 and $1,404 in aircraft costs for the nine months ended September 30, 2018 and 2017, respectively. In addition, Mr. Moelis is the other lessee of the aircraft and shares the operating and related costs of the plane in proportion to his respective use pursuant to a cost sharing and operating agreement. Promissory Notes —As of September 30, 2018, there were $189 of unsecured promissory notes from employees held by the Company (December 31, 2017: $552). Any outstanding balances are reflected in accrued and other receivables on the condensed consolidated statements of financial condition. The notes held as of September 30, 2018 and December 31, 2017 bear a fixed interest rate of 4.00%. During the nine months ended September 30, 2018 and 2017, the Company received $366 and $705 of principal repayments and recognized interest income of $11 and $20, respectively, on such notes, which is included in other income and expenses on the condensed consolidated statements of operations. Services Agreement —In connection with the Company’s IPO, the Company entered into a services agreement with a related party, Moelis Asset Management LP, whereby the Company provides certain administrative services, technology, and office space to Moelis Asset Management LP for a fee. This fee totaled $170 and $264 for the three months ended September 30, 2018 and 2017, respectively, and $479 and $868 for the nine months ended September 30, 2018 and 2017, respectively. The amount of the fee is based upon the estimated usage and related expense of all shared services between the Company and Moelis Asset Management LP during the relevant period, and will be assessed periodically by Management as per the terms of the agreement. As of September 30, 2018 and December 31, 2017, the Company had no balances due from Moelis Asset Management LP. Moelis Australia —As of September 30, 2018 and December 31, 2017, the Company had net balances due from Moelis Australia of $187 and $128, respectively, which are reflected in accrued and other receivables on the condensed consolidated statements of financial condition. These balances consist of amounts due to or from Moelis Australia for advisory services performed as well as billable expenses incurred by the Company on behalf of Moelis Australia during the period. The relationship between the Company and Moelis Australia is governed by a services agreement. Revenues —From time to time, the Company enters into advisory transactions with Moelis Asset Management LP and its affiliates. The Company earned revenues associated with such transactions of $0 and $94 for the three months ended September 30, 2018 and 2017, respectively, and revenues of $242 and $1,240 for the nine months ended September 30, 2018 and 2017, respectively.

10. RELATED-PARTY TRANSACTIONS

Aircraft Lease— On August 30, 2014, a related party, Moelis & Company Manager LLC ("Manager"), acquired an aircraft with funds received solely from its managing member (Mr. Moelis). The aircraft is used and operated by the Company pursuant to a dry lease with Manager which terminates on December 31, 2019. The terms of the dry lease are comparable to the market rates of leasing from an independent third party. Pursuant to this dry lease arrangement, the lessee is obligated to bear its share of the costs of operating the aircraft. For the three months ended September 30, 2018 and 2017, the Company incurred $468 and $468 in aircraft lease costs to be paid to Manager, respectively, and $1,404 and $1,404 in aircraft costs for the nine months ended September 30, 2018 and 2017, respectively. In addition, Mr. Moelis is the other lessee of the aircraft and shares the operating and related costs of the plane in proportion to his respective use pursuant to a cost sharing and operating agreement.

Promissory Notes —As of September 30, 2018, there were $189 of unsecured promissory notes from employees held by the Company (December 31, 2017: $552). Any outstanding balances are reflected in accrued and other receivables on the condensed consolidated statements of financial condition. The notes held as of September 30, 2018 and December 31, 2017 bear a fixed interest rate of 4.00%. During the nine months ended September 30, 2018 and 2017, the Company received $366 and $705 of principal repayments and recognized interest income of $11 and $20, respectively, on such notes, which is included in other income and expenses on the condensed consolidated statements of operations.

Services Agreement —In connection with the Company’s IPO, the Company entered into a services agreement with a related party, Moelis Asset Management LP, whereby the Company provides certain administrative services, technology, and office space to Moelis Asset Management LP for a fee. This fee totaled $170 and $264 for the three months ended September 30, 2018 and 2017, respectively, and $479 and $868 for the nine months ended September 30, 2018 and 2017, respectively. The amount of the fee is based upon the estimated usage and related expense of all shared services between the Company and Moelis Asset Management LP during the relevant period, and will be assessed periodically by Management as per the terms of the agreement. As of September 30, 2018 and December 31, 2017, the Company had no balances due from Moelis Asset Management LP.

Moelis Australia —As of September 30, 2018 and December 31, 2017, the Company had net balances due from Moelis Australia of $187 and $128, respectively, which are reflected in accrued and other receivables on the condensed consolidated statements of financial condition. These balances consist of amounts due to or from Moelis Australia for advisory services performed as well as billable expenses incurred by the Company on behalf of Moelis Australia during the period. The relationship between the Company and Moelis Australia is governed by a services agreement.

Revenues —From time to time, the Company enters into advisory transactions with Moelis Asset Management LP and its affiliates. The Company earned revenues associated with such transactions of $0 and $94 for the three months ended September 30, 2018 and 2017, respectively, and revenues of $242 and $1,240 for the nine months ended September 30, 2018 and 2017, respectively.