DEBT

9 Months Ended

Sep. 30, 2019

As of September 30, 2019, we owned 84 apartment communities, of which 35 served as collateral for mortgage loans. All of these mortgage loans were non-recourse to us other than for standard carve-out obligations. As of September 30, 2019, we believe that there are no material defaults or instances of noncompliance in regards to any of these mortgages payable.

During the three months ended September 30, 2019, we closed a $59.9 million mortgage loan. This mortgage loan is secured by four apartment communities and is priced at a fixed rate of 3.88% for the full twelve-year term of the loan. Proceeds from this loan were used to pay down balances under our line of credit.

During the three months ended September 30, 2019, we entered into a private shelf agreement for the issuance of up to $150.0 million of unsecured senior promissory notes ("unsecured senior notes"). Under this agreement, we issued $75.0 million of Series A notes due September 13, 2029 bearing interest at a rate of 3.84% annually and $50.0 million of Series B notes due September 30, 2028 bearing interest at a rate of 3.69% annually.

As of September 30, 2019, we owned 49 apartment communities that were not encumbered by mortgages, with 44 of those properties providing credit support for our unsecured borrowings. Our primary unsecured credit facility ("unsecured credit facility") is a revolving, multi-bank line of credit, with the Bank of Montreal serving as administrative agent. Our line of credit has total commitments of $250.0 million, with borrowing capacity based on the value of properties contained in the unencumbered asset pool ("UAP"). As of September 30, 2019, the UAP provided for a borrowing capacity of $250.0 million, with additional borrowing availability of $146.9 million beyond the $103.1 million drawn, including the balance on our operating line of credit (discussed below). The unsecured credit facility matures on August 31, 2022, with one twelve-month option to extend the maturity date at our election.

Under our unsecured credit facility, we also have unsecured term loans of $70.0 million and $75.0 million, included within notes payable on the condensed consolidated balance sheets, which mature on January 15, 2024 and on August 31, 2025, respectively.

The interest rates on the line of credit and term loans are based, at our option, on either the lender's base rate plus a margin, ranging from 35-85 basis points, or the London Interbank Offered Rate ("LIBOR"), plus a margin that ranges from 135-190 basis points based on our consolidated leverage. Our unsecured credit facility and unsecured senior notes are subject to customary financial covenants and limitations. We believe that we are in compliance with all such financial covenants and limitations as of September 30, 2019.

We also have a $6.0 million operating line of credit. This operating line of credit is designed to enhance treasury management activities and more effectively manage cash balances. This operating line has a one-year term, with pricing based on a market spread plus the one-month LIBOR index rate. As of September 30, 2019, we had $293,000 outstanding on this operating line compared to no outstanding balance as of December 31, 2018.

The following table summarizes our indebtedness at September 30, 2019:



	(in thousands)
	September 30, 2019			December 31, 2018			Weighted Average Maturity in Years at September 30, 2019
Lines of credit	$	103,143		$	57,500		2.9
Term loans	145,000			145,000			5.1
Unsecured senior notes	125,000			—			9.6
Unsecured debt	373,143			202,500			6.0
Mortgages payable - fixed	362,731			445,974			5.7
Total debt	$	735,874		$	648,474		5.9
Weighted average interest rate on lines of credit (rate with swap)	3.73		%	3.72		%
Weighted average interest rate on term loans (rate with swap)	4.14		%	4.01		%
Weighted average interest rate on unsecured senior notes	3.78		%	—
Weighted average interest rate on mortgages payable	4.15		%	4.58		%

The aggregate amount of required future principal payments on mortgages payable, term loans, and senior notes as of September 30, 2019, was as follows:



	(in thousands)
2019 (remainder)	$	1,599
2020	23,531
2021	55,877
2022	40,740
2023	48,359
Thereafter	462,625
Total payments	$	632,731