Stockholders' Equity (Details) (USD $) Share data in Thousands, except Per Share data, unless otherwise specified	0 Months Ended	3 Months Ended				6 Months Ended
	Feb. 07, 2014	Apr. 30, 2014	Jan. 31, 2014	Apr. 30, 2013	Jan. 31, 2013	Apr. 30, 2014	Apr. 30, 2013
Stockholders' Equity Note [Abstract]
Share Repurchase Program, maximum amount authorized						$ 500,000,000
Number of common stock repurchased, shares		0	396	0	460
Cost of common stock repurchased			50,000,000		44,400,000
Average purchase price per share			$ 126.21		$ 96.34
Share Repurchase Program, remaining authorized amount						211,500,000
Dividends on common stock	$ 1,400,000					$ 1,436,000	$ 1,449,000
Cash dividend, per share	$ 0.03
Dividends payable, date of record	Jan. 24, 2014