Condensed Consolidated Statements of Comprehensive Income (UNAUDITED) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Apr. 30, 2018	Apr. 30, 2017	Apr. 30, 2018	Apr. 30, 2017
Statement Of Income And Comprehensive Income [Abstract]
Net income	$ 91,235	$ 64,523	$ 195,790	$ 114,511
Components of other comprehensive income (loss):
Translation adjustments	(19,284)	5,849	19,298	99
Amortization of prior service cost and net actuarial losses, net of tax	2,812	1,708	4,321	3,398
Total other comprehensive income (loss)	(16,472)	7,557	23,619	3,497
Total comprehensive income	$ 74,763	$ 72,080	$ 219,409	$ 118,008