Fair value measurements (Details) (USD $) In Thousands, unless otherwise specified	Oct. 31, 2011
Assets:
Total assets at fair value	$ 15,079
Liabilities:
Deferred compensation plans	6,278
Total liabilities at fair value	7,303
Forward exchange contracts [Member]
Liabilities:
Forward exchange contracts	1,025
Level 1 [Member]
Liabilities:
Deferred compensation plans	6,278
Total liabilities at fair value	6,278
Level 1 [Member] | Forward exchange contracts [Member]
Liabilities:
Forward exchange contracts	0
Level 2 [Member]
Liabilities:
Deferred compensation plans	0
Total liabilities at fair value	1,025
Level 2 [Member] | Forward exchange contracts [Member]
Liabilities:
Forward exchange contracts	1,025
Level 3 [Member]
Liabilities:
Deferred compensation plans	0
Total liabilities at fair value	0
Level 3 [Member] | Forward exchange contracts [Member]
Liabilities:
Forward exchange contracts	0
Rabbi trust [Member]
Assets:
Rabbi trust	13,678
Forward exchange contracts [Member]
Assets:
Forward exchange contracts	1,401
Level 1 [Member]
Assets:
Total assets at fair value	0
Level 1 [Member] | Rabbi trust [Member]
Assets:
Rabbi trust	0
Level 1 [Member] | Forward exchange contracts [Member]
Assets:
Forward exchange contracts	0
Level 2 [Member]
Assets:
Total assets at fair value	15,079
Level 2 [Member] | Rabbi trust [Member]
Assets:
Rabbi trust	13,678
Level 2 [Member] | Forward exchange contracts [Member]
Assets:
Forward exchange contracts	1,401
Level 3 [Member]
Assets:
Total assets at fair value	0
Level 3 [Member] | Rabbi trust [Member]
Assets:
Rabbi trust	0
Level 3 [Member] | Forward exchange contracts [Member]
Assets:
Forward exchange contracts	$ 0