PENSION PLANS AND OTHER POST RETIREMENT BENEFITS - Schedule of the Change in Benefit Obligation (Details) - Pension Plan - USD ($) $ in Thousands	12 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2018
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Benefit obligation—beginning of fiscal year	$ 69,479	$ 61,886
Service cost	2,138	1,887	$ 1,805
Interest cost	1,164	1,431	1,337
Benefits paid	(2,362)	(1,762)
Actuarial (gain) loss	(2,823)	7,194
Foreign exchange (gain) loss	(370)	(1,157)
Benefit obligation—end of period	67,226	69,479	61,886
Less: Current portion	(1,835)	(1,811)
Non-current portion of benefit obligation	65,391	67,668
CDT defined benefit plan
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Benefit obligation—beginning of fiscal year	35,836	32,651
Service cost	572	550	501
Interest cost	459	642	607
Benefits paid	(644)	(626)
Actuarial (gain) loss	(3,073)	3,365
Foreign exchange (gain) loss	(299)	(746)
Benefit obligation—end of period	32,851	35,836	32,651
Less: Current portion	(777)	(675)
Non-current portion of benefit obligation	32,074	35,161
GXS GER defined benefit plan
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Benefit obligation—beginning of fiscal year	26,739	25,382
Service cost	319	566	472
Interest cost	337	489	489
Benefits paid	(926)	(996)
Actuarial (gain) loss	(2,083)	1,872
Foreign exchange (gain) loss	(281)	(574)
Benefit obligation—end of period	24,105	26,739	25,382
Less: Current portion	(943)	(1,012)
Non-current portion of benefit obligation	23,162	25,727
GXS PHP defined benefit plan
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Benefit obligation—beginning of fiscal year	6,904	3,853
Service cost	1,247	771	832
Interest cost	368	300	241
Benefits paid	(792)	(140)
Actuarial (gain) loss	2,333	1,957
Foreign exchange (gain) loss	210	163
Benefit obligation—end of period	10,270	6,904	$ 3,853
Less: Current portion	(115)	(124)
Non-current portion of benefit obligation	$ 10,155	$ 6,780