Mortgages and Notes Payable

The following table sets forth our mortgages and notes payable:



	September 30, 2017			December 31, 2016
Secured indebtedness	$	99,421		$	128,204
Unsecured indebtedness	1,875,239			1,826,145
Less-unamortized debt issuance costs	(8,262		)	(6,302		)
Total mortgages and notes payable, net	$	1,966,398		$	1,948,047

At September 30, 2017, our secured mortgage loans were collateralized by real estate assets with an aggregate undepreciated book value of $147.7 million.

At September 30, 2017, we had a $475.0 million unsecured revolving credit facility that was scheduled to mature in January 2018. The interest rate was LIBOR plus 110 basis points and the annual facility fee was 20 basis points. There was $72.0 million outstanding under our revolving credit facility at September 30, 2017 and $0.6 million of outstanding letters of credit, which reduced the availability on the credit facility. As a result, the unused capacity of our revolving credit facility at September 30, 2017 was $402.4 million.

During the second quarter of 2017, we prepaid without penalty a secured mortgage loan with a fair market value of $108.2 million with an effective interest rate of 4.22% that was originally scheduled to mature in November 2017. We recorded $0.4 million of gain on debt extinguishment related to this prepayment.

During 2015, we acquired our joint venture partner’s 77.2% interest in a building in Orlando. Simultaneously with this acquisition, the joint venture's previously existing mortgage note was restructured into a new $18.0 million first mortgage note and a $10.2 million subordinated note, both of which were scheduled to mature in July 2017. The first mortgage and subordinated notes had effective interest rates of 5.36% and 8.6%, respectively. The subordinated note and accrued interest thereon can be satisfied, in certain circumstances, upon payment of a "waterfall payment" equal to a cash payment of 50.0% of the amount by which the net sale proceeds or appraised value at the time of refinancing exceeded (1) the outstanding principal of the first mortgage note, (2) funds deposited by us into escrow to fund tenant improvements, leasing commissions and building improvements and (3) a 10.0% return on such funds deposited by us into escrow. As of the date of such restructuring, the subordinated note was recorded at a projected waterfall payment of $1.0 million. During the second quarter of 2017, both notes were retired upon payment of the $18.0 million principal balance on the first mortgage note and a $0.5 million waterfall payment relating to the subordinated note, which resulted in $0.4 million of gain on debt extinguishment.

During the second quarter of 2017, we obtained a $100.0 million secured mortgage loan from a third party lender with an effective interest rate of 4.0%. This loan is scheduled to mature in May 2029. We incurred $0.8 million of debt issuance costs in connection with this loan, which will be amortized over the term of the loan.

During the first quarter of 2017, the Operating Partnership issued $300.0 million aggregate principal amount of 3.875% notes due 2027, less original issue discount of $4.0 million. These notes were priced to yield 4.038%. Underwriting fees and other expenses were incurred that aggregated $2.5 million; these costs were deferred and will be amortized over the term of the notes.

During the first quarter of 2017, we paid off at maturity $379.7 million principal amount of 5.85% unsecured notes.

During the first quarter of 2017, we amended our $150.0 million unsecured bank term loan that is scheduled to mature in January 2022 by increasing the borrowed amount to $200.0 million. The interest rate on this term loan at our current credit ratings is LIBOR plus 110 basis points. The underlying LIBOR rate with respect to $50.0 million of the unsecured bank term loan has been effectively fixed for the term through floating-to-fixed interest rate swaps as discussed in Note 6. We incurred $0.3 million of debt issuance costs in connection with this amendment, which will be amortized along with existing unamortized debt issuance costs over the remaining term.

5. Mortgages and Notes Payable - Continued

We are currently in compliance with financial covenants and other requirements with respect to our consolidated debt.

We have considered our short-term liquidity needs within one year from October 24, 2017 (the date of issuance of the quarterly financial statements) and the adequacy of our estimated cash flows from operating activities and other expected financing sources to meet these needs. In particular, we have considered our scheduled debt maturities during such one-year period, including the $200.0 million principal amount of unsecured notes due April 15, 2018. We have concluded it is probable we will meet these short-term liquidity requirements through a combination of the following:


•	available cash and cash equivalents;


•	cash flows from operating activities;


•	issuance of debt securities by the Operating Partnership (some of which debt securities may be hedged to a fixed interest rate pursuant to the forward-starting swaps referred to in Note 6);


•	issuance of secured debt;


•	bank term loans;


•	borrowings under our revolving credit facility;

•issuance of equity securities by the Company or the Operating Partnership; and


•	the disposition of non-core assets.