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Financial Instruments and Fair Value Measurement - Equity Securities (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015
Available-for-sale securities
Available-for-sale securities in unrealized loss positions, number of days	30 days	30 days
Quoted Prices in Active Markets for Identical Assets (Level 1)
Non-qualified Supplemental Savings Plan
Assets held in Non-qualified Supplement Savings Plan, at fair value	$ 11,700	$ 12,900
Equity securities
Available-for-sale securities
Cost	64,462	64,462
Gross Unrealized Gains	28,895	28,530
Gross Unrealized Losses	19,829	1,509
Estimated Fair Value	$ 73,528	$ 91,483

X

- Definition

The number of days an available-for-sale security has been in an unrealized loss position.

+ References

No definition available.

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- Definition

Amount of investment in debt and equity securities categorized neither as held-to-maturity nor trading.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 25
-Paragraph 1
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Amount before tax of unrealized gain in accumulated other comprehensive income (AOCI) on investments in debt and equity securities classified as available-for-sale.

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

+ References

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+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Carrying amount as of the balance sheet date of assets held under deferred compensation agreements.

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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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