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Earnings Per Common Share (Narrative) (Details)	6 Months Ended
	Mar. 31, 2018 item
Earnings Per Share [Line Items]
Conversion feature for Class B Common Stock	each share is convertible into one share of Class A Common Stock at any time
Voting rights for shareholders	Each share of Class A Common Stock has one vote per share and each share of Class B Common Stock has ten votes per share
Percentage of cash dividend on Class B Common Stock entitled to receive for each share of Class A Common Stock	110.00%
Class A Common Stock [Member]
Earnings Per Share [Line Items]
Number of votes for common stock	1
Class B Common Stock [Member]
Earnings Per Share [Line Items]
Number of votes for common stock	10

X

- Definition

Earnings Per Share [Line Items]

+ References

No definition available.

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- Definition

Number of votes for common stock holders.

+ References

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- Definition

Percentage of cash dividend on Class B common stock entitled to receive for each share of Class A common stock.

+ References

No definition available.

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- Definition

Basis of conversion of convertible common stock.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 6
-Subparagraph (a),(c)
-URI http://asc.fasb.org/extlink&oid=84159872&loc=d3e21506-112644

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(29))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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- Definition

Description of voting rights of common stock. Includes eligibility to vote and votes per share owned. Include also, if any, unusual voting rights.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=84159872&loc=d3e21475-112644

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