Pension plans and other postretirement benefits (Tables)

6 Months Ended

Jun. 30, 2023

Retirement Benefits [Abstract]

Net Periodic Defined Benefit Cost for Defined Benefit Plans

The Company provides defined benefit pension and other postretirement benefits (including health care and life insurance benefits) to qualified retired employees. Net periodic defined benefit cost for defined benefit plans consisted of the following:

	Pension Benefits						Other Postretirement Benefits
	Three Months Ended June 30
	2023			2022			2023			2022
	(In thousands)
Service cost	$	2,952		$	4,543		$	410		$	993
Interest cost on projected benefit obligation		28,888			22,080			662			671
Expected return on plan assets		(50,230	)		(50,083	)		—			—
Amortization of prior service cost (credit)		53			133			(505	)		(311	)
Amortization of net actuarial loss (gain)		(173	)		5,322			(734	)		(416	)
Net periodic cost (benefit)	$	(18,510	)	$	(18,005	)	$	(167	)	$	937

	Pension Benefits						Other Postretirement Benefits
	Six Months Ended June 30
	2023			2022			2023			2022
	(In thousands)
Service cost	$	5,675		$	8,814		$	800		$	1,225
Interest cost on projected benefit obligation		57,723			38,347			1,406			1,026
Expected return on plan assets		(100,630	)		(87,233	)		—			—
Amortization of prior service cost (credit)		103			258			(1,030	)		(1,386	)
Amortization of net actuarial loss (gain)		(1,073	)		9,947			(1,384	)		(741	)
Net periodic cost (benefit)	$	(38,202	)	$	(29,867	)	$	(208	)	$	124