Debt and Credit Facility

6 Months Ended

Jun. 30, 2023

Debt Disclosure [Abstract]

Debt and Credit Facility

6. Debt and Credit Facility

Senior Notes

During the years ended December 31, 2021 and December 31, 2019, we issued fixed rate unsecured notes with varying maturity dates (“Senior Notes”). The stated interest rates and aggregate principal amounts of our Senior Notes were: (i) 4.50% and $550.0 million (“4.50% Senior Notes”) and (ii) 4.625% and $500.0 million (“4.625% Senior Notes”). Our Senior Notes do not require us to make any mandatory redemptions or sinking fund payments. The following table summarizes key details of our Senior Notes:

				Outstanding (in millions of dollars)
	Issuance Date	Maturity	Effective Interest Rate	As of June 30, 2023			As of December 31, 2022
4.50% Senior Notes	May 2021	June 2031	4.7%	$	550.0		$	550.0
4.625% Senior Notes	November 2019	March 2028	4.8%		500.0			500.0
Total debt					1,050.0			1,050.0
Unamortized issuance costs					(11.1	)		(11.9	)
Total carrying amount				$	1,038.9		$	1,038.1

The following table presents the fair value of our outstanding Senior Notes, which are Level 1 liabilities (in millions of dollars):

	As of June 30, 2023		As of December 31, 2022
4.50% Senior Notes	$	439.8	$	438.7
4.625% Senior Notes	$	437.3	$	440.4

Revolving Credit Facility

In October 2019, we entered into a revolving credit facility with Wells Fargo Bank, National Association, as administrative agent, and the other financial institutions party thereto, which was subsequently amended three times in March 2021, December 2021 and April 2022 (as amended, the “Revolving Credit Facility”). The Revolving Credit Facility contains a maximum commitment amount of $575.0 million (of which up to a maximum of $50.0 million may be utilized for letters of credit) and is set to mature in April 2027. Our effective interest rate on outstanding borrowings under the Revolving Credit Facility is based on the rates of Base Rate Loans and Secured Overnight Financing Rate (“SOFR”) Loans (as defined in the Revolving Credit Facility). For borrowings outstanding during the quarter and six months ended June 30, 2023, the rate for Base Rate Loans was equal to the prevailing Prime Rate plus 0.25%, while the rate for SOFR Loans, which are made for one or three month periods, was equal to the Term SOFR Reference Rate (as defined in the Revolving Credit Facility) plus 1.35%. Outstanding borrowings under the Revolving Credit Facility are reported within Long-term debt, net, on our Consolidated Balance Sheets.

The following table summarizes availability and usage of our Revolving Credit Facility as determined by a borrowing base calculated as of June 30, 2023 (in millions of dollars):

Revolving Credit Facility borrowing commitment	$	575.0
Borrowing base availability	$	575.0
Less: Outstanding borrowings under Revolving Credit Facility		(15.0	)
Less: Outstanding letters of credit under Revolving Credit Facility		(22.3	)
Remaining borrowing availability	$	537.7

Interest Expense

The following table presents interest expense relating to our Senior Notes and Revolving Credit Facility (in millions of dollars):

	Quarter Ended June 30,						Six Months Ended June 30,
	2023			2022			2023			2022
Senior Notes, including debt issuance cost amortization	$	12.4		$	12.4		$	24.8		$	24.8
Revolving Credit Facility, including commitment fees and finance cost amortization		1.2			0.6			2.1			1.0
Interest expense capitalized as construction in progress		(1.5	)		(0.8	)		(2.9	)		(1.4	)
Total interest expense	$	12.1		$	12.2		$	24.0		$	24.4