Organization	9 Months Ended
Sep. 30, 2017
Organization, Consolidation and Presentation of Financial Statements [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. Blackstone Mortgage Trust is a real estate finance company that originates and purchases senior loans collateralized by properties in North America and Europe. We are externally managed by BXMT Advisors L.L.C., or 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 an exclusion from registration under the Investment Company Act of 1940, as amended. We are organized as a holding company and conduct our business primarily through our various subsidiaries.

Organization

9 Months Ended

Sep. 30, 2017

Organization, Consolidation and Presentation of Financial Statements [Abstract]

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.

Blackstone Mortgage Trust is a real estate finance company that originates and purchases senior loans collateralized by properties in North America and Europe. We are externally managed by BXMT Advisors L.L.C., or 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 an exclusion from registration under the Investment Company Act of 1940, as amended. We are organized as a holding company and conduct our business primarily through our various subsidiaries.