Common Stock (Details) (Share repurchase program approved September 5, 2012 [Member], USD $) Share data in Millions, except Per Share data, unless otherwise specified	0 Months Ended	3 Months Ended
Sep. 05, 2012	Jul. 31, 2014
Share repurchase program approved September 5, 2012 [Member]
Equity, Class of Treasury Stock [Line Items]
Share repurchase program authorized amount	$ 50,000,000
Shares repurchased, retired, and returned to an authorized by unissued status during the period		0.4
Average price of common shares repurchased (in usd per share)		$ 26.50
Value of shares repurchased		$ 10,000,000

Stock repurchase average cost per share.

No definition available.

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- Definition

Number of shares that have been repurchased and retired during the period.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 04

-Article 3

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 505

-SubTopic 10

-Section 50

-Paragraph 2

-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21463-112644

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 29, 30

-Article 5

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- Definition

Equity impact of the value of stock that has been repurchased and retired during the period. The excess of the purchase price over par value can be charged against retained earnings (once the excess is fully allocated to additional paid in capital).

+ References

+ Details

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- Definition

Amount of a stock repurchase plan authorized by an entity's Board of Directors.

+ References

No definition available.

+ Details

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