Summary of Significant Accounting Policies	9 Months Ended
Sep. 30, 2018
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	2. Summary of Significant Accounting Policies Basis of Presentation The accompanying unaudited condensed consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America (“GAAP”) for interim financial information and the instructions to Form 10-Q and Rule 10-01 of Regulation S-X. The condensed consolidated financial statements, including the condensed notes thereto, are unaudited and exclude some of the disclosures required in audited financial statements. Management believes it has made all necessary adjustments, consisting of only normal recurring items, so that the condensed consolidated financial statements are presented fairly and that estimates made in preparing its condensed consolidated financial statements are reasonable and prudent. The accompanying unaudited condensed consolidated interim financial statements should be read in conjunction with the audited consolidated financial statements included in the Company’s Annual Report on Form 10-K for the fiscal year ended December 31, 2017 filed with the SEC. Certain amounts in the Company’s prior period condensed consolidated financial statements have been reclassified to conform to the current period presentation. The Company has chosen to aggregate certain financial statement line items in the Company’s consolidated statements of operations and consolidated statements of cash flows. Such reclassifications had no effect on net loss or previously reported totals or subtotals in the consolidated statements of cash flows. The accompanying condensed consolidated financial statements include the accounts of the Company, the Company’s subsidiaries and joint ventures in which the Company has a controlling interest. For consolidated joint ventures, the non-controlling partner’s share of the assets, liabilities and operations of the joint ventures is included in non-controlling interests as equity of the Company. The non-controlling partner’s interest is generally computed as the joint venture partner’s ownership percentage. All intercompany balances and transactions have been eliminated in consolidation. The Company consolidates partially owned entities, in which it has a controlling financial interest. In determining whether the Company has a controlling financial interest in a partially owned entity and the requirement to consolidate the accounts of that entity, the Company considers whether the entity is a variable interest entity (“VIE”) and whether it is the primary beneficiary. The Company is the primary beneficiary of a VIE when it has (i) the power to direct the most significant activities impacting the economic performance of the VIE and (ii) the obligation to absorb losses or receive benefits significant to the VIE. BREIT OP and each of the Company’s joint ventures are considered to be a VIE. The Company consolidates these entities because it has the ability to direct the most significant activities of the entities such as purchases, dispositions, financings, budgets, and overall operating plans. As of September 30, 2018, the total assets and liabilities of the Company’s consolidated VIEs, excluding BREIT OP, were $2.7 billion and $1.9 billion, respectively, compared to $947.9 million and $645.5 million as of December 31, 2017. Such amounts are included on the Company’s Condensed Consolidated Balance Sheets. The preparation of the financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosures of contingent assets and liabilities at the date of the balance sheet. Actual results could differ from those estimates. Restricted Cash As of September 30, 2018 and December 31, 2017, restricted cash primarily consists of $155.4 million and $107.6 million, respectively, of cash received for subscriptions prior to the date in which the subscriptions are effective, which is held in a bank account controlled by the Company’s transfer agent but in the name of the Company. Other restricted cash consists of amounts in escrow related to real estate taxes and insurance in connection with mortgages at certain of our properties. Fair Value Measurement Under normal market conditions, the fair value of an investment is the amount that would be received to sell an asset or transfer a liability in an orderly transaction between market participants at the measurement date (i.e., the exit price). Additionally, there is a hierarchal framework that prioritizes and ranks the level of market price observability used in measuring investments at fair value. Market price observability is impacted by a number of factors, including the type of investment and the characteristics specific to the investment and the state of the marketplace, including the existence and transparency of transactions between market participants. Investments with readily available active quoted prices or for which fair value can be measured from actively quoted prices generally will have a higher degree of market price observability and a lesser degree of judgment used in measuring fair value. Investments measured and reported at fair value are classified and disclosed in one of the following levels within the fair value hierarchy: Level 1 — quoted prices are available in active markets for identical investments as of the measurement date. The Company does not adjust the quoted price for these investments. Level 2 — quoted prices are available in markets that are not active or model inputs are based on inputs that are either directly or indirectly observable as of the measurement date. Level 3 — pricing inputs are unobservable and include instances where there is minimal, if any, market activity for the investment. These inputs require significant judgment or estimation by management or third parties when determining fair value and generally represent anything that does not meet the criteria of Levels 1 and 2. Due to the inherent uncertainty of these estimates, these values may differ materially from the values that would have been used had a ready market for these investments existed. As of September 30, 2018 and December 31, 2017, the Company’s $2.0 billion and $915.7 million, respectively, of investments in real estate-related securities were classified as Level 2. Valuation The Company’s investments in real estate-related securities are reported at fair value. As of September 30, 2018, the Company’s investments in real estate-related securities consisted of commercial mortgage-backed securities (“CMBS”), which are mortgage-related fixed income securities and corporate debt of real estate-related companies (together with CMBS, “Real Estate-Related Securities”). The Company generally determines the fair value of its Real Estate-Related Securities by utilizing third-party pricing service providers and broker-dealer quotations on the basis of last available bid price. In determining the fair value of a particular investment, pricing service providers may use broker-dealer quotations, reported trades or valuation estimates from their internal pricing models to determine the reported price. The pricing service providers’ internal models for securities such as Real Estate-Related Securities generally consider the attributes applicable to a particular class of the security (e.g., credit rating, seniority), current market data, and estimated cash flows for each class and incorporate deal collateral performance such as prepayment speeds and default rates, as available. As of September 30, 2018, the fair value of the Company’s mortgage notes, term loans, and revolving credit facilities, repurchase agreements, and affiliate line of credit was approximately $25.2 million below carrying value. Fair value of the Company’s indebtedness is estimated by modeling the cash flows required by the Company’s debt agreements and discounting them back to the present value using the appropriate discount rate. Additionally, the Company considers current market rates and conditions by evaluating similar borrowing agreements with comparable loan-to-value ratios and credit profiles. The inputs used in determining the fair value of the Company’s indebtedness are considered Level 3. Recent Accounting Pronouncements In May 2014, the FASB issued ASU 2014-09, “Revenue from Contracts with Customers (Topic 606).” ASU 2014-09 broadly amends the accounting guidance for revenue recognition. ASU 2014-09 is effective for the first interim or annual period beginning after December 15, 2017, and is to be applied retrospectively. The Company adopted ASU 2014-09 in the first quarter of 2018 and the pronouncement did not have a material impact on the Company’s condensed consolidated financial statements. In February 2016, the FASB issued ASU 2016-02, “Leases,” which will require organizations that lease assets to recognize the assets and liabilities for the rights and obligations created by those leases on their balance sheet. Additional disclosure regarding a company’s leasing activities will also be expanded under the new guidance. In July 2018, the FASB issued ASU 2018-11 which approved an amendment to the new Leases standard that allows a practical expedient for lessors from separating lease and non-lease components. For public entities, ASU 2016-02 is effective for fiscal years beginning after December 15, 2018, including interim periods within those fiscal years, and requires a modified retrospective transition. Under the new leasing standard, lessor accounting remains substantially the same as current GAAP. As such, the Company does not anticipate a material impact to its condensed consolidated financial statements from a lessor standpoint. The new lease standard will have a significant impact on lessee accounting. As such, the Company will be required to recognize a right of use asset on the Company’s consolidated balance sheet along with a lease liability equal to the present value of the remaining minimum lease payments for the Company’s ground leases. As of September 30, 2018, the undiscounted future minimum lease payments due under the Company’s long-term ground leases totaled $467.1 million. The Company is currently evaluating any further potential impact of this pronouncement on the Company’s condensed consolidated financial statements from a lessee standpoint.

2. Summary of Significant Accounting Policies

Basis of Presentation

The accompanying unaudited condensed consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America (“GAAP”) for interim financial information and the instructions to Form 10-Q and Rule 10-01 of Regulation S-X. The condensed consolidated financial statements, including the condensed notes thereto, are unaudited and exclude some of the disclosures required in audited financial statements. Management believes it has made all necessary adjustments, consisting of only normal recurring items, so that the condensed consolidated financial statements are presented fairly and that estimates made in preparing its condensed consolidated financial statements are reasonable and prudent. The accompanying unaudited condensed consolidated interim financial statements should be read in conjunction with the audited consolidated financial statements included in the Company’s Annual Report on Form 10-K for the fiscal year ended December 31, 2017 filed with the SEC.

Certain amounts in the Company’s prior period condensed consolidated financial statements have been reclassified to conform to the current period presentation. The Company has chosen to aggregate certain financial statement line items in the Company’s consolidated statements of operations and consolidated statements of cash flows. Such reclassifications had no effect on net loss or previously reported totals or subtotals in the consolidated statements of cash flows.

The accompanying condensed consolidated financial statements include the accounts of the Company, the Company’s subsidiaries and joint ventures in which the Company has a controlling interest. For consolidated joint ventures, the non-controlling partner’s share of the assets, liabilities and operations of the joint ventures is included in non-controlling interests as equity of the Company. The non-controlling partner’s interest is generally computed as the joint venture partner’s ownership percentage. All intercompany balances and transactions have been eliminated in consolidation.

The Company consolidates partially owned entities, in which it has a controlling financial interest. In determining whether the Company has a controlling financial interest in a partially owned entity and the requirement to consolidate the accounts of that entity, the Company considers whether the entity is a variable interest entity (“VIE”) and whether it is the primary beneficiary. The Company is the primary beneficiary of a VIE when it has (i) the power to direct the most significant activities impacting the economic performance of the VIE and (ii) the obligation to absorb losses or receive benefits significant to the VIE. BREIT OP and each of the Company’s joint ventures are considered to be a VIE. The Company consolidates these entities because it has the ability to direct the most significant activities of the entities such as purchases, dispositions, financings, budgets, and overall operating plans.

As of September 30, 2018, the total assets and liabilities of the Company’s consolidated VIEs, excluding BREIT OP, were $2.7 billion and $1.9 billion, respectively, compared to $947.9 million and $645.5 million as of December 31, 2017. Such amounts are included on the Company’s Condensed Consolidated Balance Sheets.

The preparation of the financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosures of contingent assets and liabilities at the date of the balance sheet. Actual results could differ from those estimates.

Restricted Cash

As of September 30, 2018 and December 31, 2017, restricted cash primarily consists of $155.4 million and $107.6 million, respectively, of cash received for subscriptions prior to the date in which the subscriptions are effective, which is held in a bank account controlled by the Company’s transfer agent but in the name of the Company. Other restricted cash consists of amounts in escrow related to real estate taxes and insurance in connection with mortgages at certain of our properties.

Fair Value Measurement

Under normal market conditions, the fair value of an investment is the amount that would be received to sell an asset or transfer a liability in an orderly transaction between market participants at the measurement date (i.e., the exit price). Additionally, there is a hierarchal framework that prioritizes and ranks the level of market price observability used in measuring investments at fair value. Market price observability is impacted by a number of factors, including the type of investment and the characteristics specific to the investment and the state of the marketplace, including the existence and transparency of transactions between market participants. Investments with readily available active quoted prices or for which fair value can be measured from actively quoted prices generally will have a higher degree of market price observability and a lesser degree of judgment used in measuring fair value.

Investments measured and reported at fair value are classified and disclosed in one of the following levels within the fair value hierarchy:

Level 1 — quoted prices are available in active markets for identical investments as of the measurement date. The Company does not adjust the quoted price for these investments.

Level 2 — quoted prices are available in markets that are not active or model inputs are based on inputs that are either directly or indirectly observable as of the measurement date.

Level 3 — pricing inputs are unobservable and include instances where there is minimal, if any, market activity for the investment. These inputs require significant judgment or estimation by management or third parties when determining fair value and generally represent anything that does not meet the criteria of Levels 1 and 2. Due to the inherent uncertainty of these estimates, these values may differ materially from the values that would have been used had a ready market for these investments existed.

As of September 30, 2018 and December 31, 2017, the Company’s $2.0 billion and $915.7 million, respectively, of investments in real estate-related securities were classified as Level 2.

Valuation

The Company’s investments in real estate-related securities are reported at fair value. As of September 30, 2018, the Company’s investments in real estate-related securities consisted of commercial mortgage-backed securities (“CMBS”), which are mortgage-related fixed income securities and corporate debt of real estate-related companies (together with CMBS, “Real Estate-Related Securities”). The Company generally determines the fair value of its Real Estate-Related Securities by utilizing third-party pricing service providers and broker-dealer quotations on the basis of last available bid price.

In determining the fair value of a particular investment, pricing service providers may use broker-dealer quotations, reported trades or valuation estimates from their internal pricing models to determine the reported price. The pricing service providers’ internal models for securities such as Real Estate-Related Securities generally consider the attributes applicable to a particular class of the security (e.g., credit rating, seniority), current market data, and estimated cash flows for each class and incorporate deal collateral performance such as prepayment speeds and default rates, as available.

As of September 30, 2018, the fair value of the Company’s mortgage notes, term loans, and revolving credit facilities, repurchase agreements, and affiliate line of credit was approximately $25.2 million below carrying value. Fair value of the Company’s indebtedness is estimated by modeling the cash flows required by the Company’s debt agreements and discounting them back to the present value using the appropriate discount rate. Additionally, the Company considers current market rates and conditions by evaluating similar borrowing agreements with comparable loan-to-value ratios and credit profiles. The inputs used in determining the fair value of the Company’s indebtedness are considered Level 3.

Recent Accounting Pronouncements

In May 2014, the FASB issued ASU 2014-09, “Revenue from Contracts with Customers (Topic 606).” ASU 2014-09 broadly amends the accounting guidance for revenue recognition. ASU 2014-09 is effective for the first interim or annual period beginning after December 15, 2017, and is to be applied retrospectively. The Company adopted ASU 2014-09 in the first quarter of 2018 and the pronouncement did not have a material impact on the Company’s condensed consolidated financial statements.

In February 2016, the FASB issued ASU 2016-02, “Leases,” which will require organizations that lease assets to recognize the assets and liabilities for the rights and obligations created by those leases on their balance sheet. Additional disclosure regarding a company’s leasing activities will also be expanded under the new guidance. In July 2018, the FASB issued ASU 2018-11 which approved an amendment to the new Leases standard that allows a practical expedient for lessors from separating lease and non-lease components. For public entities, ASU 2016-02 is effective for fiscal years beginning after December 15, 2018, including interim periods within those fiscal years, and requires a modified retrospective transition. Under the new leasing standard, lessor accounting remains substantially the same as current GAAP. As such, the Company does not anticipate a material impact to its condensed consolidated financial statements from a lessor standpoint. The new lease standard will have a significant impact on lessee accounting. As such, the Company will be required to recognize a right of use asset on the Company’s consolidated balance sheet along with a lease liability equal to the present value of the remaining minimum lease payments for the Company’s ground leases. As of September 30, 2018, the undiscounted future minimum lease payments due under the Company’s long-term ground leases totaled $467.1 million. The Company is currently evaluating any further potential impact of this pronouncement on the Company’s condensed consolidated financial statements from a lessee standpoint.