Retirement benefits (Tables)

6 Months Ended

Dec. 31, 2018

Retirement Benefits [Abstract]

Schedule of defined benefit plans disclosures

Net pension benefit cost recognized included the following components:

	Three Months Ended						Six Months Ended
	December 31,						December 31,
	2018			2017			2018			2017
Service cost	$	17,983		$	18,242		$	38,492		$	41,300
Interest cost	40,551			36,138			80,417			71,824
Expected return on plan assets	(62,701		)	(65,350		)	(125,578		)	(128,526		)
Amortization of prior service cost	1,677			1,511			3,325			3,615
Amortization of net actuarial loss	30,692			35,468			59,985			74,150
Amortization of initial net obligation	4			5			9			10
Net pension benefit cost	$	28,206		$	26,014		$	56,650		$	62,373