(1)	At both March 31, 2020 and December 31, 2019, interest rates ranged from 3.3% to 7.0% at a weighted average rate of 3.9%.


	March 31,		December 31,
	2020		2019
As to interest rate (including the effects of interest rate contracts):
Fixed-rate debt	$	1,732,193	$	1,714,890
Variable-rate debt		497,000		17,448
Total	$	2,229,193	$	1,732,338
As to collateralization:
Unsecured debt	$	1,948,229	$	1,450,762
Secured debt		280,964		281,576
Total	$	2,229,193	$	1,732,338

We maintain a $500 million unsecured revolving credit facility, which was amended and extended on December 11, 2019. This facility expires in March 2024, provides for two consecutive six-month extensions upon our request, and borrowing rates that float at a margin over LIBOR plus a facility fee. At both March 31, 2020 and December 31, 2019, the borrowing margin and facility fee, which are priced off a grid that is tied to our senior unsecured credit ratings, were 82.5 and 15 basis points, respectively. The facility also contains a competitive bid feature that allows us to request bids for up to $250 million. Additionally, an accordion feature allows us to increase the facility amount up to $850 million. As of March 31, 2020, we drew down the available balance of this credit facility to increase liquidity and preserve financial flexibility in light of the current uncertainty surrounding the impact of the COVID-19 pandemic.

Additionally, we have a $10 million unsecured short-term facility, which was amended and extended on January 3, 2020, that we maintain for cash management purposes, which matures in March 2021. At both March 31, 2020 and December 31, 2019, the facility provided for fixed interest rate loans at a 30-day LIBOR rate plus a borrowing margin, facility fee and an unused facility fee of 125, 10, and 5 basis points, respectively.

The following table discloses certain information regarding our unsecured notes payable under our credit facilities (in thousands, except percentages):


	March 31,			December 31,
	2020			2019
Unsecured revolving credit facility:
Balance outstanding	$	497,000		$	—
Available balance		946			497,946
Letters of credit outstanding under facility		2,054			2,054
Variable interest rate (excluding facility fee)		0.97	%		—	%
Unsecured short-term facility:
Balance outstanding	$	—		$	—
Variable interest rate (excluding facility fee)		—	%		—	%
Both facilities:
Maximum balance outstanding during the period	$	497,000		$	5,000
Weighted average balance		50,308			123
Year-to-date weighted average interest rate (excluding facility fee)		1.46	%		3.3	%

Related to a development project in Sheridan, Colorado, we have provided a guaranty for the payment of any debt service shortfalls until a coverage rate of 1.4x is met on tax increment revenue bonds issued in connection with the project. The bonds are to be repaid with incremental sales and property taxes and a public improvement fee (“PIF”) to be assessed on current and future retail sales and, to the extent necessary, any amounts we may have to provide under a guaranty. The incremental taxes and PIF are to remain intact until the earlier of the date the bond liability has been paid in full or 2040. Therefore, a debt service guaranty liability equal to the fair value of the amounts funded under the bonds was recorded. As of both March 31, 2020 and December 31, 2019, we had $57.4 million outstanding for the debt service guaranty liability.

During the year ended December 31, 2019, we repaid a $50 million secured fixed-rate mortgage with a 7.0% interest rate from cash from our disposition proceeds.

Various leases and properties, and current and future rentals from those leases and properties, collateralize certain debt. At both March 31, 2020 and December 31, 2019, the carrying value of such assets aggregated $.5 billion. Additionally, at both March 31, 2020 and December 31, 2019, investments of $5.3 million included in Restricted Deposits and Escrows are held as collateral for letters of credit totaling $5.0 million.

Scheduled principal payments on our debt (excluding $497 million outstanding under our revolving credit facility, $21.8 million of a finance lease obligation, $(3.7) million net premium/(discount) on debt, $(5.4) million of deferred debt costs, $1.9 million of non-cash debt-related items, and $57.4 million debt service guaranty liability) are due during the following years (in thousands):


2020 remaining	$	4,227
2021		18,795
2022		308,298
2023		348,207
2024		252,561
2025		294,232
2026		277,733
2027		53,604
2028		92,159
2029		917
Thereafter		9,518
Total	$	1,660,251

Our various debt agreements contain restrictive covenants, including minimum interest and fixed charge coverage ratios, minimum unencumbered interest coverage ratios, minimum net worth requirements and maximum total debt levels. We are not aware of any non-compliance with our public debt and revolving credit facility covenants as of March 31, 2020; however, our continued compliance with these covenants depends on many factors and could be impacted by current or future economic conditions associated with the COVID-19 pandemic.