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Debt and Preferred Equity Investments - Additional Information (Details) - USD ($) $ in Thousands | 9 Months Ended |  |
--- | --- | --- | ---
Sep. 30, 2018 | Dec. 31, 2017 | Sep. 30, 2014
Mortgage Loans on Real Estate [Line Items] |  |  |
Aggregate weighted average current yield (as a percent) | 8.92% |  |
Debt Investments Held [Abstract] |  |  |
Carrying Value | $ 1,977,057 | $ 2,114,041 |
Mezzanine Loan with an Initial Maturity Date of March 2020 |  |  |
Debt Investments Held [Abstract] |  |  |
Amount participated out | 1,300 |  |
Mezzanine Loan, with an Initial Maturity Date of June 2024 |  |  |
Debt Investments Held [Abstract] |  |  |
Amount participated out | 12,000 |  |
Mezzanine Loan with an Initial Maturity Date of December 2018 |  |  |
Debt Investments Held [Abstract] |  |  |
Amount participated out | 14,600 |  |
Mezzanine Loan with an Initial Maturity Date of December 2018, 2 |  |  |
Debt Investments Held [Abstract] |  |  |
Amount participated out | 14,100 |  |
Mezzanine Loan with an Initial Maturity of March 2019 |  |  |
Debt Investments Held [Abstract] |  |  |
Amount participated out | 5,100 |  |
Debt Investments in Mortgage Loans |  |  |
Debt Investments Held [Abstract] |  |  |
Future Funding Obligations | 171,399 |  |
Senior Financing | 6,709,946 |  |
Carrying Value | 1,832,006 | 1,969,618 |
Total fixed rate |  |  |
Debt Investments Held [Abstract] |  |  |
Future Funding Obligations | 0 |  |
Senior Financing | 3,893,189 |  |
Carrying Value | 401,221 | 669,968 |
Total fixed rate | Mezzanine Loan with an Initial Maturity Date of March 2020 |  |  |
Debt Investments Held [Abstract] |  |  |
Future Funding Obligations | 0 |  |
Senior Financing | 1,160,000 |  |
Carrying Value | 210,832 | 204,005 |
Total fixed rate | Mezzanine Loan, September 2021 |  |  |
Debt Investments Held [Abstract] |  |  |
Future Funding Obligations | 0 |  |
Senior Financing | 15,000 |  |
Carrying Value | 3,500 | 3,500 |
Total fixed rate | Mezzanine Loan with an Initial Maturity Date of April 2022 |  |  |
Debt Investments Held [Abstract] |  |  |
Future Funding Obligations | 0 |  |
Senior Financing | 147,000 |  |
Carrying Value | 24,927 | 24,913 |
Total fixed rate | Mezzanine Loan with an Initial Maturity of August 2022 |  |  |
Debt Investments Held [Abstract] |  |  |
Future Funding Obligations | 0 |  |
Senior Financing | 280,000 |  |
Carrying Value | 36,069 | 34,600 |
Total fixed rate | Mezzanine Loan, November 2023 |  |  |
Debt Investments Held [Abstract] |  |  |
Future Funding Obligations | 0 |  |
Senior Financing | 83,689 |  |
Carrying Value | 12,704 | 12,699 |
Total fixed rate | Mezzanine Loan, with an Initial Maturity Date of June 2024 |  |  |
Debt Investments Held [Abstract] |  |  |
Future Funding Obligations | 0 |  |
Senior Financing | 115,000 |  |
Carrying Value | 12,939 | 12,932 |
Total fixed rate | Mezzanine Loan, January 2025 |  |  |
Debt Investments Held [Abstract] |  |  |
Future Funding Obligations | 0 |  |
Senior Financing | 95,000 |  |
Carrying Value | 30,000 | 30,000 |
Total fixed rate | Mezzanine Loan with an Initial Maturity Date of November 2026 |  |  |
Debt Investments Held [Abstract] |  |  |
Future Funding Obligations | 0 |  |
Senior Financing | 340,000 |  |
Carrying Value | 15,000 | 15,000 |
Total fixed rate | Mezzanine Loan with an Initial Maturity Date of June 2027 |  |  |
Debt Investments Held [Abstract] |  |  |
Future Funding Obligations | 0 |  |
Senior Financing | 1,657,500 |  |
Carrying Value | 55,250 | 55,250 |
Total fixed rate | Real Estate Acquired in Satisfaction of Debt |  |  |
Debt Investments Held [Abstract] |  |  |
Future Funding Obligations | 0 |  |
Senior Financing | 0 |  |
Carrying Value | 0 | 250,464 |
Total fixed rate | Mezzanine Loan Repaid In August 2018 |  |  |
Debt Investments Held [Abstract] |  |  |
Future Funding Obligations | 0 |  |
Senior Financing | 0 |  |
Carrying Value | 0 | 26,366 |
Total fixed rate | Mortgage Loan Repaid In September 2018 |  |  |
Debt Investments Held [Abstract] |  |  |
Future Funding Obligations | 0 |  |
Senior Financing | 0 |  |
Carrying Value | 0 | 239 |
Total fixed rate | Mortgage Loan, February 2019 |  |  |
Debt Investments Held [Abstract] |  |  |
Loan acquired |  |  | $ 26,400
Discount amount |  |  | 200
Total fixed rate | Junior Mortgage Participation, Related To Mortgage Loan, February 2019 |  |  |
Debt Investments Held [Abstract] |  |  |
Loan acquired |  |  | 5,700
Discount amount |  |  | $ 5,700
Total floating rate |  |  |
Debt Investments Held [Abstract] |  |  |
Future Funding Obligations | 171,399 |  |
Senior Financing | 2,816,757 |  |
Carrying Value | 1,430,785 | 1,299,650 |
Total floating rate | Mezzanine Loan with an Initial Maturity Date of March 2020 |  |  |
Debt Investments Held [Abstract] |  |  |
Future Funding Obligations | 2,944 |  |
Senior Financing | 312,310 |  |
Carrying Value | 51,669 | 0 |
Total floating rate | Mezzanine Loan with an Initial Maturity Date of August 2018 |  |  |
Debt Investments Held [Abstract] |  |  |
Future Funding Obligations | 0 |  |
Senior Financing | 20,523 |  |
Carrying Value | 10,977 | 10,934 |
Total floating rate | Mezzanine Loan with an Initial Maturity Date of October 2018 |  |  |
Debt Investments Held [Abstract] |  |  |
Future Funding Obligations | 2,325 |  |
Senior Financing | 45,025 |  |
Carrying Value | 35,168 | 34,879 |
Total floating rate | Mezzanine Loan with an Initial Maturity Date of December 2018 |  |  |
Debt Investments Held [Abstract] |  |  |
Future Funding Obligations | 0 |  |
Senior Financing | 150,000 |  |
Carrying Value | 15,368 | 15,381 |
Total floating rate | Mezzanine Loan with an Initial Maturity Date of December 2018, 2 |  |  |
Debt Investments Held [Abstract] |  |  |
Future Funding Obligations | 0 |  |
Senior Financing | 0 |  |
Carrying Value | 14,856 | 14,869 |
Total floating rate | Mezzanine Loan with an Initial Maturity Date of December 2018, 3 |  |  |
Debt Investments Held [Abstract] |  |  |
Future Funding Obligations | 0 |  |
Senior Financing | 33,000 |  |
Carrying Value | 26,987 | 26,927 |
Total floating rate | Mezzanine Loan with an Initial Maturity Date of January 2019 |  |  |
Debt Investments Held [Abstract] |  |  |
Future Funding Obligations | 3,607 |  |
Senior Financing | 30,438 |  |
Carrying Value | 10,403 | 8,550 |
Total floating rate | Mezzanine Loan with an Initial Maturity of March 2019 |  |  |
Debt Investments Held [Abstract] |  |  |
Future Funding Obligations | 795 |  |
Senior Financing | 0 |  |
Carrying Value | 15,150 | 15,148 |
Total floating rate | Mezzanine Loan with an Initial Maturity of March 2019, 2 |  |  |
Debt Investments Held [Abstract] |  |  |
Future Funding Obligations | 0 |  |
Senior Financing | 38,000 |  |
Carrying Value | 21,977 | 21,939 |
Total floating rate | Mezzanine Loan with an Initial Maturity Date of April 2019 |  |  |
Debt Investments Held [Abstract] |  |  |
Future Funding Obligations | 0 |  |
Senior Financing | 40,000 |  |
Carrying Value | 19,972 | 19,982 |
Total floating rate | Mezzanine Loan with an Initial Maturity Date of April 2019, 2 |  |  |
Debt Investments Held [Abstract] |  |  |
Future Funding Obligations | 0 |  |
Senior Financing | 37,891 |  |
Carrying Value | 18,380 | 34,947 |
Total floating rate | Mezzanine Loan With An Initial Maturity Date Of April 2019, 3 |  |  |
Debt Investments Held [Abstract] |  |  |
Future Funding Obligations | 0 |  |
Senior Financing | 175,000 |  |
Carrying Value | 37,404 | 37,250 |
Total floating rate | Mezzanine Loan With An Initial Maturity Date Of April 2019, 4 |  |  |
Debt Investments Held [Abstract] |  |  |
Future Funding Obligations | 0 |  |
Senior Financing | 265,000 |  |
Carrying Value | 24,928 | 24,830 |
Total floating rate | Mortgage/Jr Mortgage Participate Loan, Maturity Date of August 2019 |  |  |
Debt Investments Held [Abstract] |  |  |
Future Funding Obligations | 17,186 |  |
Senior Financing | 228,516 |  |
Carrying Value | 82,517 | 71,832 |
Total floating rate | Mortgage/Mezzanine Loan With An Initial Maturity Date Of August 2019 |  |  |
Debt Investments Held [Abstract] |  |  |
Future Funding Obligations | 0 |  |
Senior Financing | 0 |  |
Carrying Value | 19,999 | 19,940 |
Total floating rate | Mezzanine Loan With An Initial Maturity Date Of August 2019 |  |  |
Debt Investments Held [Abstract] |  |  |
Future Funding Obligations | 0 |  |
Senior Financing | 65,000 |  |
Carrying Value | 14,998 | 14,955 |
Total floating rate | Mortgage/Mezzanine Loan with an Initial Maturity of September 2019 |  |  |
Debt Investments Held [Abstract] |  |  |
Future Funding Obligations | 5,905 |  |
Senior Financing | 0 |  |
Carrying Value | 180,339 | 143,919 |
Total floating rate | Mezzanine Loan with an Initial Maturity of October 2019 |  |  |
Debt Investments Held [Abstract] |  |  |
Future Funding Obligations | 0 |  |
Senior Financing | 350,000 |  |
Carrying Value | 34,847 | 34,737 |
Total floating rate | Mortgage/Mezzanine Loan with an Initial Maturity Date of December 2019 |  |  |
Debt Investments Held [Abstract] |  |  |
Future Funding Obligations | 387 |  |
Senior Financing | 0 |  |
Carrying Value | 39,338 | 0 |
Total floating rate | Mortgage/Mezzanine Loan with an Initial Maturity of January 2020 |  |  |
Debt Investments Held [Abstract] |  |  |
Future Funding Obligations | 13,048 |  |
Senior Financing | 0 |  |
Carrying Value | 56,624 | 43,845 |
Total floating rate | Mezzanine Loan with an Initial Maturity of January 2020 |  |  |
Debt Investments Held [Abstract] |  |  |
Future Funding Obligations | 812 |  |
Senior Financing | 574,120 |  |
Carrying Value | 78,841 | 75,834 |
Total floating rate | Mortgage Loan with an Initial Maturity of February 2020 |  |  |
Debt Investments Held [Abstract] |  |  |
Future Funding Obligations | 13,579 |  |
Senior Financing | 0 |  |
Carrying Value | 86,058 | 0 |
Total floating rate | Mortgage and Mezzanine Loan with an Initial Maturity Date of April 2020 |  |  |
Debt Investments Held [Abstract] |  |  |
Future Funding Obligations | 27,776 |  |
Senior Financing | 0 |  |
Carrying Value | 288,811 | 0 |
Total floating rate | Mezzanine Loan with an Initial Maturity of July 2020 |  |  |
Debt Investments Held [Abstract] |  |  |
Future Funding Obligations | 6,095 |  |
Senior Financing | 36,786 |  |
Carrying Value | 12,141 | 11,259 |
Total floating rate | Mezzanine Loan with an Initial Maturity of November 2020 |  |  |
Debt Investments Held [Abstract] |  |  |
Future Funding Obligations | 41,309 |  |
Senior Financing | 355,148 |  |
Carrying Value | 85,955 | 75,428 |
Total floating rate | Mortgage/Mezzanine Loan with an Initial Maturity of December 2020 |  |  |
Debt Investments Held [Abstract] |  |  |
Future Funding Obligations | 35,631 |  |
Senior Financing | 0 |  |
Carrying Value | 96,185 | 88,989 |
Total floating rate | Mortgage/Mezzanine Loan with an Initial Maturity of December 2020, 2 |  |  |
Debt Investments Held [Abstract] |  |  |
Future Funding Obligations | 0 |  |
Senior Financing | 0 |  |
Carrying Value | 35,236 | 35,152 |
Total floating rate | Jr Mortgage Participation/Mezzanine Loan with an Initial Maturity of July 2021 |  |  |
Debt Investments Held [Abstract] |  |  |
Future Funding Obligations | 0 |  |
Senior Financing | 60,000 |  |
Carrying Value | 15,657 | 15,635 |
Total floating rate | Mortgage/Mezzanine Loan Repaid In February 2018, 2 |  |  |
Debt Investments Held [Abstract] |  |  |
Future Funding Obligations | 0 |  |
Senior Financing | 0 |  |
Carrying Value | 0 | 162,553 |
Total floating rate | Mortgage/Mezzanine Loan repaid in June 2017 |  |  |
Debt Investments Held [Abstract] |  |  |
Future Funding Obligations | 0 |  |
Senior Financing | 0 |  |
Carrying Value | 0 | 74,755 |
Total floating rate | Mortgage/Mezzanine Loan Sold In May 2018 |  |  |
Debt Investments Held [Abstract] |  |  |
Future Funding Obligations | 0 |  |
Senior Financing | 0 |  |
Carrying Value | 0 | 23,609 |
Total floating rate | Mezzanine Loan Exchanged For Property In July 2018 |  |  |
Debt Investments Held [Abstract] |  |  |
Future Funding Obligations | 0 |  |
Senior Financing | 0 |  |
Carrying Value | 0 | 12,174 |
Total floating rate | Mezzanine Loan Repaid In July 2018 |  |  |
Debt Investments Held [Abstract] |  |  |
Future Funding Obligations | 0 |  |
Senior Financing | 0 |  |
Carrying Value | 0 | 37,851 |
Total floating rate | Mezzanine Loan Repaid In July 2018, 2 |  |  |
Debt Investments Held [Abstract] |  |  |
Future Funding Obligations | 0 |  |
Senior Financing | 0 |  |
Carrying Value | 0 | 14,855 |
Total floating rate | Mortgage/Mezzanine Loan Repaid In August 2018 |  |  |
Debt Investments Held [Abstract] |  |  |
Future Funding Obligations | 0 |  |
Senior Financing | 0 |  |
Carrying Value | 0 | 16,969 |
Total floating rate | Mezzanine Loan Repaid In September 2018 |  |  |
Debt Investments Held [Abstract] |  |  |
Future Funding Obligations | 0 |  |
Senior Financing | 0 |  |
Carrying Value | $ 0 | $ 59,723 |

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- Definition Amount before allowance of loans and leases held in portfolio, including but not limited to, commercial and consumer loans. Includes deferred interest and fees, undisbursed portion of loan balance, unamortized costs and premiums and discounts from face amounts. Excludes loans and leases covered under loss sharing agreements. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 45 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=82891408&loc=d3e4428-111522 + Details
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