Debt and Credit Agreements

The Company's debt and credit agreements consisted of the following:



	December 31,
(In thousands)	2018			2017
Total debt
6.51% weighted-average senior notes ⁽¹⁾	$	124,000		$	361,000
9.78% senior notes ⁽²⁾	—			67,000
5.58% weighted-average senior notes	175,000			175,000
3.65% weighted-average senior notes	925,000			925,000
Revolving credit facility	7,000			—
Unamortized debt issuance costs	(4,896		)	(6,109		)
	$	1,226,104		$	1,521,891

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(1)	Includes $237.0 million of current portion of long-term debt at December 31, 2017.


(2)	Includes $67.0 million of current portion of long-term debt at December 31, 2017.

The Company has debt maturities of $87.0 million due in 2020, $188.0 million due in 2021 and $62.0 million due in 2023 associated with its senior notes. In addition, the revolving credit facility matures in April 2020. No other tranches of debt are due within the next five years.

At December 31, 2018, the Company was in compliance with all restrictive financial covenants for both its revolving credit facility and senior notes.

Senior Notes

The Company has various issuances of senior notes. Interest on each of the senior notes is payable semi-annually. Under the terms of the various senior note agreements, the Company may prepay all or any portion of the notes of each series on any date at a price equal to the principal amount thereof plus accrued and unpaid interest plus a make-whole premium.

The Company's agreements provide that the Company maintain a minimum asset coverage ratio of 1.75 to 1.0 and a minimum annual coverage ratio of consolidated cash flow to interest expense for the trailing four quarters of 2.8 to 1.0. There are also various other covenants and events of default customarily found in such debt instruments.

6.51% Weighted-Average Senior Notes

In July 2008, the Company issued $425.0 million of senior unsecured notes to a group of 41 institutional investors in a private placement. The notes have bullet maturities and were issued in three separate tranches as follows:



	Principal		Term	Maturity Date	Coupon
Tranche 1	$	245,000,000	10 years	July 2018	6.44	%
Tranche 2	$	100,000,000	12 years	July 2020	6.54	%
Tranche 3	$	80,000,000	15 years	July 2023	6.69	%

In May 2016, the Company repurchased $8.0 million of Tranche 1, $13.0 million of Tranche 2 and $43.0 million of Tranche 3 for a total of $64.0 million for $68.3 million. The Company recognized a $4.7 million extinguishment loss associated with the premium paid and the write-off of a portion of the related deferred financing costs due to early repayment.

As of December 31, 2018, the Company has repaid $301.0 million of aggregate principal amount associated with the 6.51% weighted-average senior notes.

5.58% Weighted-Average Senior Notes

In December 2010, the Company issued $175.0 million of senior unsecured notes to a group of eight institutional investors in a private placement. The notes have bullet maturities and were issued in three separate tranches as follows:



	Principal		Term	Maturity Date	Coupon
Tranche 1	$	88,000,000	10 years	January 2021	5.42	%
Tranche 2	$	25,000,000	12 years	January 2023	5.59	%
Tranche 3	$	62,000,000	15 years	January 2026	5.80	%

3.65% Weighted‑Average Senior Notes

In September 2014, the Company issued $925.0 million of senior unsecured notes to a group of 24 institutional investors in a private placement. The notes have bullet maturities and were issued in three separate tranches as follows:



	Principal		Term	Maturity Date	Coupon
Tranche 1	$	100,000,000	7 years	September 2021	3.24	%
Tranche 2	$	575,000,000	10 years	September 2024	3.67	%
Tranche 3	$	250,000,000	12 years	September 2026	3.77	%

Revolving Credit Agreement

The Company's revolving credit facility is unsecured. The borrowing base is redetermined annually under the terms of the revolving credit facility on April 1. In addition, either the Company or the banks may request an interim redetermination twice a year or in conjunction with certain acquisitions or sales of oil and gas properties. Effective April 18, 2018, the Company’s borrowing base and available commitments were reaffirmed at $3.2 billion and $1.7 billion, respectively. The Company's revolving credit facility matures in April 2020.

Interest rates under the revolving credit facility are based on LIBOR or ABR indications, plus a margin which ranges from 50 to 225 basis points, as defined in the agreement. The revolving credit facility also provides for a commitment fee on the unused available balance at annual rates ranging from 0.30 percent to 0.50 percent.

The revolving credit facility contains various other customary covenants, which include the following (with all calculations based on definitions contained in the agreement):


(a)	Maintenance of a minimum asset coverage ratio of 1.75 to 1.0.


(b)	Maintenance of a minimum annual coverage ratio of consolidated cash flow to interest expense for the trailing four quarters of 2.8 to 1.0.


(c)	Maintenance of a minimum current ratio of 1.0 to 1.0.

At December 31, 2018, the Company had $7.0 million of borrowings outstanding under its revolving credit facility and had unused commitments of $1.8 billion. The Company's weighted-average effective interest rate for the revolving credit facility during the year ended December 31, 2018 and 2016 was approximately 6.3 percent and 2.3 percent, respectively. There were no outstanding borrowings during 2017.