CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2019	Mar. 31, 2018
Document Period End Date			Mar. 31, 2019
Net income (loss)	$ 77,332	$ (164,053)	$ 96,422	$ (110,825)
Other comprehensive income (loss):
Foreign currency translation adjustment	5,255	4,096	(3,047)	5,611
Pension Adjustments	46	0	(314)	116
Unrealized (loss) gain on marketable securities	158	(71)	156	(348)
Total other comprehensive income (loss), net	5,459	4,025	(3,205)	5,379
Comprehensive income (loss)	$ 82,791	$ (160,028)	$ 93,217	$ (105,446)