Auction Rate Securities - Narrative (Details)		6 Months Ended
May 16, 2018 USD ($)	Apr. 30, 2018 USD ($) institution	Oct. 31, 2017 USD ($) institution
Schedule of Available-for-sale Securities [Line Items]
Number of different auction rate securities issuers \| institution		2	2
Interest rate reset interval		30 days
Auction Rate Securities
Schedule of Available-for-sale Securities [Line Items]
Investment in auction rate securities, original principal amount		$ 10,000,000	$ 10,000,000
Investment in auction rate securities, amortized cost basis		8,000,000	8,000,000
Investment in auction rate securities, fair value		8,000,000	8,000,000
Unrealized holding gain (loss) on securities		0	0
Auction Rate Securities \| Retained Earnings
Schedule of Available-for-sale Securities [Line Items]
Total amount of other-than-temporary impairment (OTTI) credit loss recognized		$ 2,000,000	$ 2,000,000
Subsequent Event \| Auction Rate Securities
Schedule of Available-for-sale Securities [Line Items]
Investment in auction rate securities, amortized cost basis	$ 3,000,000
Available-for-sale debt securities, original par value	5,000,000
Proceeds from sale of AFS securities, debt	$ 2,900,000

Available-for-sale Debt Securities, Original Par Value

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This item represents the original cost of debt securities, which are categorized neither as held-to-maturity nor trading, excluding adjustments such as accretion, amortization, collection of cash, previous other-than-temporary impairments recognized in earnings (less any cumulative-effect adjustments recognized, as defined), and fair value hedge accounting adjustments, if any.

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The period of time in which the interest rates for auction rate securities reset through auctions.

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The number of different issuers of the auction rate securities held by the Company.

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Amount before tax of unrealized gain in accumulated other comprehensive income (AOCI) on investments in debt securities classified as available-for-sale.

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Amount of debt securities categorized neither as held-to-maturity nor trading.

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The cumulative amount of credit losses recognized in earnings related to debt securities held for which a portion of an other than temporary impairment (OTTI) was recognized in other comprehensive income (a component of shareholders' equity).

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The cash inflow associated with the sale of debt securities classified as available-for-sale securities.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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