Long-Term Debt - Credit Agreement Additional Information (Detail)	Nov. 30, 2016	Nov. 03, 2016 USD ($)	Apr. 30, 2017 USD ($)	Oct. 31, 2016 USD ($)	Dec. 19, 2012 USD ($)
Debt Instrument [Line Items]
Less deferred financing costs			$ 7,600,000	$ 0
Long-term debt			1,056,200,000	974,600,000
Current portion of long-term debt			15,000,000	0
Long-term debt, excluding current maturities			$ 1,033,600,000	974,600,000
2017 Credit Agreement
Debt Instrument [Line Items]
Debt issued		$ 300,000,000.0
Optional additional borrowing capacity		$ 550,000,000
Leverage ratio, adjusted EBITDA	4.00
Leverage ratio, adjusted EBITDA during collateral release period		3.75
Interest coverage ratio, adjusted EBITDA		3.00
Weighted average interest rate			1.86%
Actual interest rate			2.22%
Revolving Credit Facility | 2017 Credit Agreement
Debt Instrument [Line Items]
Maximum borrowing capacity		$ 800,000,000
Reduction in outstanding letter of credit			$ 11,900,000
Less deferred financing costs			6,300,000
Long-term debt			433,900,000	0
Current portion of long-term debt			15,000,000
Long-term debt, excluding current maturities			418,900,000
Line of Credit | Prior Credit Agreement
Debt Instrument [Line Items]
Maximum borrowing capacity					$ 1,000,000,000
Current borrowing available			650,500,000
Amount used to pay outstanding obligations and costs and expenses incurred		$ 208,000,000
Long-term debt			$ 0	$ 201,200,000