Comprehensive income (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Jan. 31, 2012	Jan. 31, 2011
Summary of comprehensive income
Net income	$ 38,338	$ 45,897
Foreign currency translation adjustments	(8,354)	(6,832)
Amortization of prior service cost and net actuarial losses	2,712	1,550
Total comprehensive income (loss)	32,696	40,615
Components of activity for accumulated other comprehensive loss
Beginning Balance	(80,012)	(66,306)
Current-period change	(5,642)	(5,282)
Ending Balance	$ (85,654)	$ (71,588)