UNSECURED AND SECURED DEBT (Tables)

12 Months Ended

Dec. 31, 2020

Debt Disclosure [Abstract]

Schedule of long-term debt instruments

	December 31,
	2020		2019
	(In thousands)
Unsecured bank credit facilities - variable rate, carrying amount	$	125,000	112,710
Unamortized debt issuance costs	(806)		(1,316)
Unsecured bank credit facilities	124,194		111,394
Unsecured debt - fixed rate, carrying amount (1)	1,110,000		940,000
Unamortized debt issuance costs	(2,292)		(1,885)
Unsecured debt	1,107,708		938,115
Secured debt - fixed rate, carrying amount (1)	79,096		133,422
Unamortized debt issuance costs	(103)		(329)
Secured debt	78,993		133,093
Total debt	$	1,310,895	1,182,602

(1)These loans have a fixed interest rate or an effectively fixed interest rate due to interest rate swaps.

Schedule of unsecured debt

A summary of the carrying amount of Unsecured debt follows:

				Balance at December 31,
	Margin Above LIBOR	Interest Rate	Maturity Date	2020		2019
				(In thousands)
$75 Million Unsecured Term Loan (1)	1.10%	3.45%	12/20/2020	$	—	75,000
$40 Million Unsecured Term Loan (1)	1.10%	2.34%	07/30/2021	40,000		40,000
$75 Million Unsecured Term Loan (1)	1.40%	3.03%	02/28/2022	75,000		75,000
$65 Million Unsecured Term Loan (1)	1.10%	2.31%	04/01/2023	65,000		65,000
$100 Million Senior Unsecured Notes:
$30 Million Notes	Not applicable	3.80%	08/28/2020	—		30,000
$50 Million Notes	Not applicable	3.80%	08/28/2023	50,000		50,000
$20 Million Notes	Not applicable	3.80%	08/28/2025	20,000		20,000
$60 Million Senior Unsecured Notes	Not applicable	3.46%	12/13/2024	60,000		60,000
$100 Million Senior Unsecured Notes:
$60 Million Notes	Not applicable	3.48%	12/15/2024	60,000		60,000
$40 Million Notes	Not applicable	3.75%	12/15/2026	40,000		40,000
$25 Million Senior Unsecured Notes	Not applicable	3.97%	10/01/2025	25,000		25,000
$50 Million Senior Unsecured Notes	Not applicable	3.99%	10/07/2025	50,000		50,000
$60 Million Senior Unsecured Notes	Not applicable	3.93%	04/10/2028	60,000		60,000
$80 Million Senior Unsecured Notes	Not applicable	4.27%	03/28/2029	80,000		80,000
$35 Million Senior Unsecured Notes	Not applicable	3.54%	08/15/2031	35,000		35,000
$75 Million Senior Unsecured Notes	Not applicable	3.47%	08/19/2029	75,000		75,000
$100 Million Unsecured Term Loan (1)	1.50%	2.75%	10/10/2026	100,000		100,000
$100 Million Unsecured Term Loan (1)	1.45%	2.39%	03/25/2027	100,000		—
$100 Million Senior Unsecured Notes	Not applicable	2.61%	10/14/2030	100,000		—
$75 Million Senior Unsecured Notes	Not applicable	2.71%	10/14/2032	75,000		—
				$	1,110,000	940,000

(1)The interest rates on these unsecured term loans are comprised of LIBOR plus a margin which is subject to a pricing grid for changes in the Company's coverage ratings. The Company entered into interest rate swap agreements (further described in Note 13) to convert the loans' LIBOR rates to effectively fixed interest rates. The interest rates in the table above are the effectively fixed interest rates for the loans, including the effects of the interest rate swaps, as of December 31, 2020.

Schedule of secured debt

A summary of the carrying amount of Secured debt follows: 

	Interest Rate	Monthly Principal & Interest Payment	Maturity Date	Carrying Amount of Securing Real Estate at December 31, 2020		Balance at December 31,
Property						2020	2019
				(In thousands)
40th Avenue, Beltway Crossing V, Centennial Park, Executive Airport, Interchange Park I, Ocean View, Wetmore 5-8 and World Houston 26, 28, 29 & 30	4.39%	463,778	Repaid	$	—	—	48,772
Colorado Crossing, Interstate I-III, Rojas, Steele Creek 1 & 2, Venture and World Houston 3-9 (1)	4.75%	420,045	06/05/2021	47,774		41,610	44,596
Arion 18, Beltway Crossing VI & VII, Commerce Park II & III, Concord, Interstate V-VII, Lakeview, Ridge Creek II, Southridge IV & V and World Houston 32	4.09%	329,796	01/05/2022	52,034		35,220	37,682
Ramona	3.85%	16,287	11/30/2026	8,697		2,266	2,372
				$	108,505	79,096	133,422

(1)During 2019, the Company executed a collateral release for World Houston 5; this property was sold during 2019 and is no longer considered to be collateral securing this loan.

Principal payments due during the next five years

Scheduled principal payments on long-term debt, including Unsecured debt and Secured debt (not including Unsecured bank credit facilities), due during the next five years as of December 31, 2020 are as follows: 

Years Ending December 31,	(In thousands)
2021	$	84,285
2022	107,770
2023	115,119
2024	120,122
2025	95,128