Organization	9 Months Ended
Sep. 30, 2013
Accounting Policies [Abstract]
Organization	1. ORGANIZATION References herein to “Blackstone Mortgage Trust,” “Company,” “we,” “us” or “our” refer to Blackstone Mortgage Trust, Inc. and its subsidiaries unless the context specifically requires otherwise. We are a real estate finance company that primarily originates and purchases senior mortgage loans collateralized by properties in the United States and Europe. We are externally managed by BXMT Advisors L.L.C., which we refer to as our Manager, a subsidiary of The Blackstone Group L.P., or Blackstone, and are a real estate investment trust, or REIT, traded on the New York Stock Exchange, or NYSE, under the symbol “BXMT.” We are headquartered in New York City. We conduct our operations as a REIT for U.S. federal income tax purposes. We generally will not be subject to U.S. federal income taxes on our taxable income to the extent that we annually distribute all of our net taxable income to stockholders and maintain our qualification as a REIT. We also operate our business in a manner that permits us to maintain our exemption from registration under the Investment Company Act of 1940, as amended, or the Investment Company Act. We are organized as a holding company and conduct our business primarily through our various subsidiaries. Our business is organized into two operating segments: the Loan Origination segment and the CT Legacy Portfolio segment. On April 26, 2013, our board of directors approved the change of our name from Capital Trust, Inc. to Blackstone Mortgage Trust, Inc., which we effected on May 6, 2013 concurrently with a one-for-ten reverse stock split of our class A common stock. Except where the context indicates otherwise, all class A common stock numbers herein have been adjusted to give retroactive effect to the reverse stock split.

1. ORGANIZATION

References herein to “Blackstone Mortgage Trust,” “Company,” “we,” “us” or “our” refer to Blackstone Mortgage Trust, Inc. and its subsidiaries unless the context specifically requires otherwise.

We are a real estate finance company that primarily originates and purchases senior mortgage loans collateralized by properties in the United States and Europe. We are externally managed by BXMT Advisors L.L.C., which we refer to as our Manager, a subsidiary of The Blackstone Group L.P., or Blackstone, and are a real estate investment trust, or REIT, traded on the New York Stock Exchange, or NYSE, under the symbol “BXMT.” We are headquartered in New York City.

We conduct our operations as a REIT for U.S. federal income tax purposes. We generally will not be subject to U.S. federal income taxes on our taxable income to the extent that we annually distribute all of our net taxable income to stockholders and maintain our qualification as a REIT. We also operate our business in a manner that permits us to maintain our exemption from registration under the Investment Company Act of 1940, as amended, or the Investment Company Act. We are organized as a holding company and conduct our business primarily through our various subsidiaries. Our business is organized into two operating segments: the Loan Origination segment and the CT Legacy Portfolio segment.

On April 26, 2013, our board of directors approved the change of our name from Capital Trust, Inc. to Blackstone Mortgage Trust, Inc., which we effected on May 6, 2013 concurrently with a one-for-ten reverse stock split of our class A common stock. Except where the context indicates otherwise, all class A common stock numbers herein have been adjusted to give retroactive effect to the reverse stock split.