Stock-Based Compensation - Performance-based Awards (Details) - USD ($)	1 Months Ended	9 Months Ended
Oct. 31, 2016	Apr. 30, 2017
Stock-based awards, additional disclosure
Total unrecognized stock-based compensation expense, before income taxes, related to total nonvested stock options and stock awards (in dollars)		$ 10,963,000
Remaining weighted average period over which unrecognized stock-based compensation expense is expected to be recognized		20 months
Performance Share Units
Stock-based awards, additional disclosure
Maximum attainment of initial grant (as a percent)		200.00%
TSR-Based
Stock-based awards, additional disclosure
Vesting period	3 years

The percentage of maximum attainment of initial grant .

No definition available.

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- Definition

Unrecognized cost of unvested share-based compensation awards.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (i)
-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

+ Details

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- Definition

Weighted average period over which unrecognized compensation is expected to be recognized for equity-based compensation plans, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

+ Details

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- References

No definition available.

+ Details

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- Definition

Period which an employee's right to exercise an award is no longer contingent on satisfaction of either a service condition, market condition or a performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (a)(1)
-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

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- Details

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