PENSION PLANS AND OTHER POST RETIREMENT BENEFITS - Components of Net Pension Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2018
Assumptions:
Net pension expense	$ 5,802	$ 4,624	$ 3,738
Interest cost, location	us-gaap:NonoperatingIncomeExpense
Amortization of actuarial (gains) losses, location	us-gaap:NonoperatingIncomeExpense
Pension Plan
Assumptions:
Service cost	$ 2,138	1,887	1,805
Interest cost	1,164	1,431	1,337
Amortization of actuarial (gains) and losses	895	264	372
Net pension expense	4,197	3,582	3,514
Pension Plan | CDT defined benefit plan
Assumptions:
Service cost	572	550	501
Interest cost	459	642	607
Amortization of actuarial (gains) and losses	939	696	541
Net pension expense	1,970	1,888	1,649
Pension Plan | GXS GER defined benefit plan
Assumptions:
Service cost	319	566	472
Interest cost	337	489	489
Amortization of actuarial (gains) and losses	244	130	72
Net pension expense	900	1,185	1,033
Pension Plan | GXS PHP defined benefit plan
Assumptions:
Service cost	1,247	771	832
Interest cost	368	300	241
Amortization of actuarial (gains) and losses	(288)	(562)	(241)
Net pension expense	$ 1,327	$ 509	$ 832