Preferred and Common Stock - Additional information (Detail) - USD ($)	Oct. 31, 2015	Sep. 02, 2015	Sep. 01, 2015	Oct. 31, 2014
Class of Stock [Line Items]
Preferred stock, shares authorized	500,000			500,000
Preferred stock, shares issued	0			0
Stock repurchase program, remaining authorized amount			$ 10,000,000
Maximum
Class of Stock [Line Items]
Stock repurchase program, authorized amount			$ 50,000,000.0
2015 Share Repurchase Program
Class of Stock [Line Items]
Stock repurchase program, remaining authorized amount	$ 188,600,000
2015 Share Repurchase Program | Maximum
Class of Stock [Line Items]
Stock repurchase program, authorized amount		$ 200,000,000.0