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Fair Value Measurements Available-For-Sale Securities (Details) - USD ($) $ in Thousands | Jun. 30, 2017 | Sep. 30, 2016
--- | --- | ---
Schedule Of Available For Sale Securities [Line Items] |  |
Available For Sale Securities Amortized Cost | $ 80,036 | $ 65,572
Gross Unrealized Gain | 9,658 | 7,729
Gross Unrealized Loss | (83) | (600)
Fair value | 89,611 | 72,701
Available-for-sale Securities, Other Disclosure Items [Abstract] |  |
Available-for-sale Securities, Supplemental Executive Benefit Plans | 42,300 | 41,300
Equity Funds Domestic [Member] |  |
Schedule Of Available For Sale Securities [Line Items] |  |
Available For Sale Securities Amortized Cost | 25,236 | 26,692
Gross Unrealized Gain | 7,749 | 6,419
Gross Unrealized Loss | (17) | (590)
Fair value | 32,968 | 32,521
Equity Funds Foreign [Member] |  |
Schedule Of Available For Sale Securities [Line Items] |  |
Available For Sale Securities Amortized Cost | 4,581 | 4,954
Gross Unrealized Gain | 1,857 | 1,202
Gross Unrealized Loss | 0 | 0
Fair value | 6,438 | 6,156
Fixed Income Funds [Member] |  |
Schedule Of Available For Sale Securities [Line Items] |  |
Available For Sale Securities Amortized Cost | 15,928 |
Gross Unrealized Gain | 0 |
Gross Unrealized Loss | (36) |
Fair value | 15,892 |
Debt Securities [Member] |  |
Schedule Of Available For Sale Securities [Line Items] |  |
Available For Sale Securities Amortized Cost | 31,407 | 31,296
Gross Unrealized Gain | 52 | 108
Gross Unrealized Loss | (30) | (10)
Fair value | 31,429 | 31,394
Money Market Funds [Member] |  |
Schedule Of Available For Sale Securities [Line Items] |  |
Available For Sale Securities Amortized Cost | 2,884 | 2,630
Gross Unrealized Gain | 0 | 0
Gross Unrealized Loss | 0 | 0
Fair value | $ 2,884 | $ 2,630

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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 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=65884222&loc=d3e22054-111558 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 5 -Subparagraph (aa) -URI http://asc.fasb.org/extlink&oid=73527792&loc=d3e27232-111563 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 45 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=66010992&loc=d3e26610-111562 + Details
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