Debt | Debt The Company’s mortgage loans and its senior secured revolving credit facility are collateralized by first-mortgage liens on certain of the Company’s properties. The mortgages are non-recourse except for instances of fraud or misapplication of funds. Mortgage debt consisted of the following (dollars in thousands): Collateral Interest Rate Maturity Date 6/30/15 Balance Outstanding on Loan as of June 30, 2015 December 31, Senior Secured Revolving Credit Facility (1) 2.67 % November 5, 2016 $ 238,773 $ — $ 22,500 SpringHill Suites by Marriott Washington, PA (2) 5.84 % April 1, 2015 — — 4,760 Courtyard by Marriott Altoona, PA 5.96 % April 1, 2016 10,347 6,064 6,172 Residence Inn by Marriott New Rochelle, NY 5.75 % September 1, 2021 21,025 14,665 14,832 Residence Inn by Marriott San Diego, CA 4.66 % February 6, 2023 46,364 29,809 30,062 Homewood Suites by Hilton San Antonio, TX 4.59 % February 6, 2023 29,256 17,028 17,174 Residence Inn by Marriott Vienna, VA 4.49 % February 6, 2023 32,367 23,330 23,534 Courtyard by Marriott Houston, TX 4.19 % May 6, 2023 31,890 19,300 19,475 Hyatt Place Pittsburgh, PA 4.65 % July 6, 2023 37,573 23,464 23,657 Residence Inn by Marriott Bellevue, WA 4.97 % December 6, 2023 69,033 47,244 47,580 Residence Inn by Marriott Garden Grove, CA 4.79 % April 6, 2024 42,309 34,000 34,000 Residence Inn by Marriott Silicon Valley I, CA 4.64 % July 1, 2024 88,286 64,800 64,800 Residence Inn by Marriott Silicon Valley II, CA 4.64 % July 1, 2024 96,734 70,700 70,700 Residence Inn by Marriott San Mateo, CA 4.64 % July 1, 2024 69,664 48,600 48,600 Residence Inn by Marriott Mountain View, CA 4.64 % July 6, 2024 53,309 37,900 37,900 SpringHill Suites by Marriott Savannah, GA 4.62 % July 6, 2024 37,592 30,000 30,000 Homewood Suites by Hilton Billerica, MA 4.32 % December 6, 2024 11,889 16,225 16,225 Homewood Suites by Hilton Carlsbad CA 4.32 % December 6, 2024 28,447 19,950 19,950 Hampton Inn & Suites Houston Medical Center, TX 4.25 % January 6, 2025 15,432 18,300 18,300 Total $ 960,290 $ 521,379 $ 550,221 (1) Twelve properties in the borrowing base serve as collateral for borrowings under the senior secured revolving credit facility at June 30, 2015 . The interest rate for the senior secured revolving credit facility is variable and based on LIBOR plus 2.5% . (2) On March 31, 2015 , the Company paid off the SpringHill Suites by Marriott Washington, PA loan, due April 1, 2015 . At June 30, 2015 and December 31, 2014 , the Company had $0 and $22,500 , respectively, of outstanding borrowings under its senior secured revolving credit facility. At June 30, 2015 , the maximum borrowing availability under the senior secured revolving credit facility was $175,000 . The Company estimates the fair value of its fixed rate debt, which is all of the Company's mortgage loans, by discounting the future cash flows of each instrument at estimated market rates. Rates take into consideration general market conditions, quality and estimated value of collateral and maturity of debt with similar credit terms and are classified within level 3 of the fair value hierarchy. The estimated fair value of the Company’s fixed rate debt as of June 30, 2015 and December 31, 2014 was $524,742 and $542,538 , respectively. The Company estimates the fair value of its variable rate debt by taking into account general market conditions and the estimated credit terms it could obtain for debt with similar maturity and is classified within level 3 of the fair value hierarchy. The Company’s only variable rate debt is under its senior secured revolving credit facility. The estimated fair value of the Company’s variable rate debt as of June 30, 2015 and December 31, 2014 was $0 and $22,498 , respectively. As of June 30, 2015 , the Company was in compliance with all of its financial covenants. At June 30, 2015 , the Company’s consolidated fixed charge coverage ratio was 3.13 . Future scheduled principal payments of debt obligations as of June 30, 2015 , for the current year and each of the next four calendar years and thereafter are as follows (in thousands): Amount 2015 (remaining six months) $ 1,586 2016 9,487 2017 3,901 2018 4,954 2019 6,899 Thereafter 494,552 Total $ 521,379 |