Indebtedness

At December 31, 2018 and 2017, our outstanding indebtedness included the following (in thousands):



				December 31,
	Interest Rate at December 31, 2018		Maturity Date	2018			2017
Unsecured revolving credit facility, at LIBOR plus a premium	—	%	—	$	—		$	—
5-year unsecured term loan, at LIBOR plus a premium	—	%	—	—			200,000
7-year unsecured term loan, at LIBOR plus a premium	—	%	—	—			200,000
Unsecured floating rate debt	—	%		$	—		$	400,000

5.875% Senior Unsecured Notes due 2020	5.875	%	9/15/2020	$	250,000		$	250,000
5.75% Senior Unsecured Notes due 2042	—	%	—	—			175,000
Unsecured fixed rate debt	5.875	%		$	250,000		$	425,000

206 East 9th Street	5.69	%	1/5/2021	$	26,000		$	26,536
97 Newberry Road	—	%	—	—			5,404
Secured fixed rate debt	5.69	%		$	26,000		$	31,940
				$	276,000		$	856,940
Unamortized net premiums, discounts and deferred financing fees				(1,045		)	(8,362		)
				$	274,955		$	848,578

Unsecured Revolving Credit Facility and Term Loan:

On January 29, 2015, we entered into a new credit agreement, pursuant to which the lenders agreed to provide (i) a $750.0 million unsecured revolving credit facility, (ii) a $200.0 million 5-year term loan facility and (iii) a $200.0 million 7-year term loan facility. The new agreement replaced our prior credit agreement, dated as of August 9, 2010, and our prior term loan agreement, dated as of December 16, 2010.

On November 10, 2016, in connection with our conversion to an UPREIT structure, the Operating Trust entered into an amended and restated credit agreement, replacing the Company’s prior credit agreement. Under the amended and restated credit agreement, the Operating Trust has assumed all obligations of the Company as borrower and the Company is released from such obligations. The economic terms of the amended and restated credit agreement are substantially the same as the terms of the Company’s prior credit agreement.

On May 4, 2018, we redeemed at par the total $400.0 million outstanding under our 5-year and 7-year term loans and recognized a loss on early extinguishment of debt of $1.5 million from the write off of unamortized deferred financing fees. Prior to the redemption of the term loans, borrowings under the 5-year term loan and 7-year term loan, subject to certain exceptions, had interest rates of LIBOR rate plus a margin of 90 to 180 basis points for the 5-year term loan and 140 to 235 basis points for the 7-year term loan, in each case depending on our credit rating.

On December 26, 2018, we terminated the credit agreement and recognized a loss on early extinguishment of debt of $0.2 million from the write off of unamortized deferred financing fees. We were required to pay a facility fee of 12.5 to 30 basis points, depending on our credit rating, on the borrowings available under the revolving credit facility, whether or not utilized.

Debt Covenants:

Our public debt indenture and related supplements contain a number of financial ratio covenants which generally restrict our ability to incur debts, in excess of calculated amounts, and require us to maintain other financial ratios. At December 31, 2018, we believe we were in compliance with all of our respective covenants under our public debt indenture and related supplements.

Senior Unsecured Notes:

On March 7, 2018, we redeemed at par all $175.0 million of our 5.75% senior unsecured notes due 2042 and recognized a loss on early extinguishment of debt of $4.9 million from the write off of unamortized deferred financing fees.

On July 15, 2017, we redeemed at par $250.0 million of our 6.65% senior unsecured notes due 2018 and recognized a loss on early extinguishment of debt of $0.2 million for the year ended December 31, 2017 from the write off of unamortized deferred financing fees and the write off of an unamortized discount.

On December 15, 2016, we redeemed at par $250.0 million of our 6.25% senior unsecured notes due 2017 and recognized a loss on early extinguishment of debt of $0.1 million for the year ended December 31, 2016 from the write-off of an unamortized discount and unamortized deferred financing fees.

On February 16, 2016, we redeemed at par $139.1 million of our 6.25% senior unsecured notes due 2016 and recognized a loss on early extinguishment of debt of $0.1 million for the year ended December 31, 2016 from the write-off of an unamortized discount and unamortized deferred financing fees.

Mortgage Notes Payable:

At December 31, 2018, one of our properties with an aggregate net book value of $44.3 million had a secured mortgage note totaling $26.5 million (including a net premium and unamortized deferred financing fees) maturing in 2021.

In December 2018, we repaid $4.9 million of mortgage debt at 97 Newberry Road and recognized a loss on early extinguishment of debt of $0.6 million for the year ended December 31, 2018 from prepayment fees and the write off of unamortized deferred financing fees.

In December 2017, we repaid $2.0 million of mortgage debt at 33 Stiles Lane and recognized a loss on early extinguishment of debt of $0.2 million for the year ended December 31, 2017 from prepayment fees and the write off of unamortized deferred financing fees.

In April 2017, we repaid at par $41.3 million of mortgage debt at Parkshore Plaza and recognized a loss on early extinguishment of debt of $0.1 million for the year ended December 31, 2017 from prepayment fees and the write off of unamortized deferred financing fees, net of the write off of an unamortized premium.

On November 10, 2016, we repaid at par $167.8 million of mortgage debt at 1735 Market Street and recognized a loss on early extinguishment of debt of $2.4 million from the write-off of unamortized deferred financing fees and breakage costs for the year ended December 31, 2016. We also recognized $0.2 million of expense included in interest and other income related to an interest rate swap as a result of the early repayment of debt for the year ended December 31, 2016.

Required Principal Payments:

The required principal payments due during the next five years and thereafter under all of our outstanding debt at December 31, 2018 are as follows (in thousands):



2019	$	567
2020	250,597
2021	24,836
2022	—
2023	—
Thereafter	—
	$	276,000