Retirement benefits (Tables)

9 Months Ended

Mar. 31, 2024

Retirement Benefits [Abstract]

Net pension (benefit) expense

Net pension (benefit) expense recognized included the following components:

	Three Months Ended				Nine Months Ended
	March 31,				March 31,
	2024		2023		2024		2023
Service cost	$	12,646	$	14,599	$	38,593	$	42,534
Interest cost	67,644		59,021		202,077		166,456
Expected return on plan assets	(88,381)		(80,137)		(264,862)		(228,695)
Amortization of prior service cost	319		227		955		679
Amortization of net actuarial loss (gain)	1,992		(657)		5,967		12,625
Net pension (benefit) expense	$	(5,780)	$	(6,947)	$	(17,270)	$	(6,401)