Related Party Transactions	12 Months Ended
Dec. 31, 2016
Related Party Transactions [Abstract]
Related Party Transactions	Related Party Transactions AMTG Merger As fully described in "Note 19- Business Combination", in August 2016, the Company acquired AMTG, an entity managed by an affiliate of Apollo. Management Agreement In connection with the Company’s initial public offering in September 2009, the Company entered into a management agreement (the “Management Agreement”) with ACREFI Management, LLC (the “Manager”), which describes the services to be provided by the Manager and its compensation for those services. The Manager is responsible for managing the Company’s day-to-day operations, subject to the direction and oversight of the Company’s board of directors. Pursuant to the terms of the Management Agreement, the Manager is paid a base management fee equal to 1.5% per annum of the Company’s stockholders’ equity (as defined in the Management Agreement), calculated and payable (in cash) quarterly in arrears. The current term of the Management Agreement expires on September 29, 2017 and is automatically renewed for successive one-year terms on each anniversary thereafter. The Management Agreement may be terminated upon expiration of the one-year extension term only upon the affirmative vote of at least two-thirds of the Company’s independent directors, based upon (1) unsatisfactory performance by the Manager that is materially detrimental to the Company or (2) a determination that the management fee payable to the Manager is not fair, subject to the Manager’s right to prevent such a termination based on unfair fees by accepting a mutually acceptable reduction of management fees agreed to by at least two-thirds of the Company’s independent directors. The Manager must be provided with written notice of any such termination at least 180 days prior to the expiration of the then existing term and will be paid a termination fee equal to three times the sum of the average annual base management fee during the 24-month period immediately preceding the date of termination, calculated as of the end of the most recently completed fiscal quarter prior to the date of termination. Following a meeting by the Company’s independent directors in February 2017, which included a discussion of the Manager’s performance and the level of the management fees thereunder, the Company determined not to seek termination of the Management Agreement. As described in "Note 16 - Commitments and Contingencies," the Company also made payments to the Manager in accordance with its letter agreement with the Manager. For 2016, 2015 and 2014, respectively, the Company incurred approximately $23,388, $16,619 and $11,960 in base management fees under the Management Agreement. In addition to the base management fee, the Company is also responsible for reimbursing the Manager for certain expenses paid by the Manager on behalf of the Company or for certain services provided by the Manager to the Company. For 2016, 2015 and 2014, respectively, the Company recorded expenses totaling $2,526, $1,421 and $985 related to reimbursements for certain expenses paid by the Manager on behalf of the Company under the Management Agreement. Expenses incurred by the Manager and reimbursed by the Company are reflected in the respective consolidated statement of operations expense category or the consolidated balance sheet based on the nature of the item. Expenses incurred by the Manager and reimbursed by the Company are reflected in the respective condensed consolidated statement of operations expense category or the condensed consolidated balance sheet based on the nature of the item. Included in payable to related party on the consolidated balance sheet at December 31, 2016 and December 31, 2015, respectively, is approximately $7,015 and $5,297 for base management fees incurred but not yet paid. Unconsolidated Joint Venture In September 2014, the Company, through a wholly owned subsidiary, acquired a 59% ownership interest in Champ LP following which a wholly-owned subsidiary of Champ LP then acquired a 35% ownership interest in BKB. The Company acquired its ownership interest in Champ LP for an initial purchase price paid at closing of approximately €30,724 (or $39,477). The Company committed to invest up to approximately €38,000 (or $50,000). In January 2015, the Company funded an additional investment of €3,331 (or $3,929) related to its investment in Champ LP. In February 2015, the Company sold approximately 48% of its ownership interest in Champ LP at cost to an account managed by Apollo for approximately €16,314 (or $20,794). In June 2016, the Company transferred €427 of its unfunded commitment to Apollo, reducing its unfunded commitment to Champ LP to €2,802 (or $2,947). Through its interest in Champ LP, as of December 31, 2016, the Company held an indirect ownership interest of approximately 9.34% in BKB. The Company together with certain other affiliated investors and unaffiliated third party investors, in aggregate, own 100% of BKB. Placement Agent Fees In connection with the private placement that closed on September 21, 2015, the Company agreed to pay a placement agent fee of $500 to Apollo Global Securities, LLC. See "Note 15 - Stockholders' Equity" for further information related to the private placement. GE Capital and Mubadala Loan Portfolio On September 29, 2015, the Company entered into a commitment to purchase a real estate loan portfolio from Mubadala GE Capital Ltd representing approximately $375,355 of first mortgage real estate loans (the “Real Estate Loans”). The commitment was part of a larger transaction in which affiliates of Apollo agreed to acquire a portfolio of loans from Mubadala GE Capital Ltd (the “Transaction”). On October 1, 2015, the Company and MidCap FinCo Limited (“MidCap”), an affiliate of Apollo, entered into an agreement (the “MidCap Agreement”) whereby the Company granted MidCap an option to purchase the Real Estate Loans. In consideration of the option, MidCap paid the Company a fee of $750 during the fourth quarter of 2015. On December 2, 2015, MidCap provided the Company written notice that it exercised its option to purchase the Real Estate Loans, and upon such exercise, the Company transferred, assigned and conveyed to MidCap all of the Company’s right, title and interest to purchase the Real Estate Loans under the Company’s commitment with Mubadala GE Capital Ltd. Increase and Extension of Mezzanine Loan for London, U.K. Pre-development Project On October 5, 2016, the Company entered into a twelve month extension and increased the Company’s outstanding loan amount through the acquisition of an additional £45,000 (approximately $57,400) of pari passu interests in an existing pre-development mezzanine loan from various funds managed by an affiliate of the Company’s manager, bringing the Company's total outstanding loan balance to £100,000 (approximately $123,400). The pre-development mezzanine loan is for the development of a luxury condominium project in London, England.

Related Party Transactions

AMTG Merger

As fully described in "Note 19- Business Combination", in August 2016, the Company acquired AMTG, an entity managed by an affiliate of Apollo.

Management Agreement

In connection with the Company’s initial public offering in September 2009, the Company entered into a management agreement (the “Management Agreement”) with ACREFI Management, LLC (the “Manager”), which describes the services to be provided by the Manager and its compensation for those services. The Manager is responsible for managing the Company’s day-to-day operations, subject to the direction and oversight of the Company’s board of directors.

Pursuant to the terms of the Management Agreement, the Manager is paid a base management fee equal to 1.5% per annum of the Company’s stockholders’ equity (as defined in the Management Agreement), calculated and payable (in cash) quarterly in arrears.

The current term of the Management Agreement expires on September 29, 2017 and is automatically renewed for successive one-year terms on each anniversary thereafter. The Management Agreement may be terminated upon expiration of the one-year extension term only upon the affirmative vote of at least two-thirds of the Company’s independent directors, based upon (1) unsatisfactory performance by the Manager that is materially detrimental to the Company or (2) a determination that the management fee payable to the Manager is not fair, subject to the Manager’s right to prevent such a termination based on unfair fees by accepting a mutually acceptable reduction of management fees agreed to by at least two-thirds of the Company’s independent directors. The Manager must be provided with written notice of any such termination at least 180 days prior to the expiration of the then existing term and will be paid a termination fee equal to three times the sum of the average annual base management fee during the 24-month period immediately preceding the date of termination, calculated as of the end of the most recently completed fiscal quarter prior to the date of termination. Following a meeting by the Company’s independent directors in February 2017, which included a discussion of the Manager’s performance and the level of the management fees thereunder, the Company determined not to seek termination of the Management Agreement. As described in "Note 16 - Commitments and Contingencies," the Company also made payments to the Manager in accordance with its letter agreement with the Manager.

For 2016, 2015 and 2014, respectively, the Company incurred approximately $23,388, $16,619 and $11,960 in base management fees under the Management Agreement. In addition to the base management fee, the Company is also responsible for reimbursing the Manager for certain expenses paid by the Manager on behalf of the Company or for certain services provided by the Manager to the Company. For 2016, 2015 and 2014, respectively, the Company recorded expenses totaling $2,526, $1,421 and $985 related to reimbursements for certain expenses paid by the Manager on behalf of the Company under the Management Agreement. Expenses incurred by the Manager and reimbursed by the Company are reflected in the respective consolidated statement of operations expense category or the consolidated balance sheet based on the nature of the item. Expenses incurred by the Manager and reimbursed by the Company are reflected in the respective condensed consolidated statement of operations expense category or the condensed consolidated balance sheet based on the nature of the item.

Included in payable to related party on the consolidated balance sheet at December 31, 2016 and December 31, 2015, respectively, is approximately $7,015 and $5,297 for base management fees incurred but not yet paid.

Unconsolidated Joint Venture

In September 2014, the Company, through a wholly owned subsidiary, acquired a 59% ownership interest in Champ LP following which a wholly-owned subsidiary of Champ LP then acquired a 35% ownership interest in BKB. The Company acquired its ownership interest in Champ LP for an initial purchase price paid at closing of approximately €30,724 (or $39,477). The Company committed to invest up to approximately €38,000 (or $50,000).

In January 2015, the Company funded an additional investment of €3,331 (or $3,929) related to its investment in Champ LP. In February 2015, the Company sold approximately 48% of its ownership interest in Champ LP at cost to an account managed by Apollo for approximately €16,314 (or $20,794). In June 2016, the Company transferred €427 of its unfunded commitment to Apollo, reducing its unfunded commitment to Champ LP to €2,802 (or $2,947). Through its interest in Champ LP, as of December 31, 2016, the Company held an indirect ownership interest of approximately 9.34% in BKB. The Company together with certain other affiliated investors and unaffiliated third party investors, in aggregate, own 100% of BKB.

Placement Agent Fees

In connection with the private placement that closed on September 21, 2015, the Company agreed to pay a placement agent fee of $500 to Apollo Global Securities, LLC. See "Note 15 - Stockholders' Equity" for further information related to the private placement.

GE Capital and Mubadala Loan Portfolio

On September 29, 2015, the Company entered into a commitment to purchase a real estate loan portfolio from Mubadala GE Capital Ltd representing approximately $375,355 of first mortgage real estate loans (the “Real Estate Loans”). The commitment was part of a larger transaction in which affiliates of Apollo agreed to acquire a portfolio of loans from Mubadala GE Capital Ltd (the “Transaction”). On October 1, 2015, the Company and MidCap FinCo Limited (“MidCap”), an affiliate of Apollo, entered into an agreement (the “MidCap Agreement”) whereby the Company granted MidCap an option to purchase the Real Estate Loans. In consideration of the option, MidCap paid the Company a fee of $750 during the fourth quarter of 2015.

On December 2, 2015, MidCap provided the Company written notice that it exercised its option to purchase the Real Estate Loans, and upon such exercise, the Company transferred, assigned and conveyed to MidCap all of the Company’s right, title and interest to purchase the Real Estate Loans under the Company’s commitment with Mubadala GE Capital Ltd.

Increase and Extension of Mezzanine Loan for London, U.K. Pre-development Project

On October 5, 2016, the Company entered into a twelve month extension and increased the Company’s outstanding loan amount through the acquisition of an additional £45,000 (approximately $57,400) of pari passu interests in an existing pre-development mezzanine loan from various funds managed by an affiliate of the Company’s manager, bringing the Company's total outstanding loan balance to £100,000 (approximately $123,400). The pre-development mezzanine loan is for the development of a luxury condominium project in London, England.