CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2017	Dec. 31, 2016
Statement of Comprehensive Income [Abstract]
Net income for the period	$ 84,917	$ 45,034	$ 121,607	$ 957,945
Other comprehensive income (loss)—net of tax:
Net foreign currency translation adjustments	(1,446)	(11,526)	(540)	(10,307)
Unrealized gain (loss) on cash flow hedges:
Unrealized gain (loss) - net of tax expense (recovery) effect of ($60) and ($252) for the three months ended December 31, 2017 and 2016, respectively; $403 and ($380) for the six months ended December 31, 2017 and 2016, respectively	(168)	(698)	1,117	(1,053)
(Gain) loss reclassified into net income - net of tax (expense) recovery effect of ($141) and ($33) for the three months ended December 31, 2017 and 2016, respectively; ($428) and ($38) for the six months ended December 31, 2017 and 2016, respectively	(391)	(91)	(1,188)	(108)
Actuarial gain (loss) relating to defined benefit pension plans:
Actuarial gain (loss) - net of tax expense (recovery) effect of ($153) and $1,077 for the three months ended December 31, 2017 and 2016, respectively; ($236) and $484 for the six months ended December 31, 2017 and 2016, respectively	(48)	2,823	(163)	4,361
Amortization of actuarial (gain) loss into net income - net of tax (expense) recovery effect of $43 and $57 for the three months ended December 31, 2017 and 2016, respectively; $85 and $119 for the six months ended December 31, 2017 and 2016, respectively	56	134	112	281
Unrealized net gain (loss) on marketable securities - net of tax effect of nil for the three and six months ended December 31, 2017 and 2016, respectively	0	512	0	400
Release of unrealized gain on marketable securities - net of tax effect of nil for the three and six months ended December 31, 2017 and 2016, respectively	0	0	(617)	0
Total other comprehensive income (loss) net, for the period	(1,997)	(8,846)	(1,279)	(6,426)
Total comprehensive income	82,920	36,188	120,328	951,519
Comprehensive (income) loss attributable to non-controlling interests	194	(12)	100	(39)
Total comprehensive income attributable to OpenText	$ 83,114	$ 36,176	$ 120,428	$ 951,480