Auction Rate Securities - Significant Assumptions Used to Determine Fair Value of Auction Rate Securities (Detail)	0 Months Ended
	Jul. 31, 2014	Oct. 31, 2013	Jul. 31, 2014	Oct. 31, 2013
Schedule of Available-for-sale Securities
Libor plus stated yield	2.00%	2.00%	2.00%	2.00%
Yields	2.15%	2.15%	2.15%	2.15%
Minimum
Schedule of Available-for-sale Securities
Libor plus the stated discount rate			0.31%	0.33%
Average Expected Life, Auction Rate Securities	4 years	4 years
Maximum
Schedule of Available-for-sale Securities
Libor plus the stated discount rate			4.41%	3.01%
Average Expected Life, Auction Rate Securities	10 years	10 years