UNAUDITED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	3 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
UNAUDITED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME [Abstract]
Net income (loss)	$ (3,083)	$ 22,231
Other comprehensive income (loss), net of tax:
Foreign currency translation adjustments	7,144	(17,574)
Unrealized loss on available-for-sale securities	(46)	0
Net unrealized gain on cash flow hedges	199	666
Other comprehensive income (loss), net of tax	7,297	(16,908)
Comprehensive income	$ 4,214	$ 5,323