Accumulated Other Comprehensive Income (Loss) (Details) - USD ($)	3 Months Ended						9 Months Ended
	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Mar. 31, 2019	Mar. 31, 2018
Accumulated Other Comprehensive Income (Loss) [Line Items]
Net change in accumulated other comprehensive income (loss)	$ 20,892,000	$ (27,948,000)	$ (13,519,000)	$ 37,767,000	$ 8,341,000	$ 33,787,000	$ (20,575,000)	$ 79,895,000
Foreign currency translation adjustments [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other comprehensive income (loss) before reclassifications	20,934,000			37,868,000			(20,533,000)	80,065,000
Deferred gains/(losses) on cash flow hedging instruments [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other comprehensive income (loss) before reclassifications	(42,000)			0			(42,000)	39,000
Amounts reclassified into income	0			0			0	(106,000)
Amounts reclassified into income for deferred gains/(losses) on cash flow hedging instruments	0			0			0	132,000
Unrealized gain/(loss) on available for sale investment [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other comprehensive income (loss) before reclassifications	0			(101,000)			0	(103,000)
Intra-entity foreign currency transactions [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other comprehensive income (loss) before reclassifications	$ (403,000)			$ 670,000			$ (875,000)	$ 1,736,000