Significant Assumptions Used to Determine Fair Value of Auction Rate Securities (Detail)	Jan. 31, 2014	Oct. 31, 2013
Schedule of Available-for-sale Securities [Line Items]
Yields	2.15%	2.15%
Libor plus stated yield	2.00%	2.00%
Minimum
Schedule of Available-for-sale Securities [Line Items]
Libor plus the stated discount rate	0.39%	0.33%
Average expected lives	4	4
Maximum
Schedule of Available-for-sale Securities [Line Items]
Libor plus the stated discount rate	3.56%	3.01%
Average expected lives	10	10