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Aggregate number of common shares reserved for future issuance.

+ References

Reference 1: 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

Number of shares that have been repurchased during the period and have not been retired and are not held in treasury. Some state laws may govern the circumstances under which an entity may acquire its own stock and prescribe the accounting treatment therefore. This element is used when state law does not recognize treasury stock.

+ 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 during the period and has not been retired and is not held in treasury. Some state laws may mandate the circumstances under which an entity may acquire its own stock and prescribe the accounting treatment therefore. This element is used when state law does not recognize treasury stock.

+ References

+ Details

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- Definition

Amount of stock repurchase plan authorized.

+ References

No definition available.

+ Details

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- Definition

The number of shares authorized to be repurchased by an entity's Board of Directors under a stock repurchase plan.

+ References

No definition available.

+ Details

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- Definition

Shares of common stock reserved for conversion.

+ References

No definition available.

+ Details

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- Definition

Represents the conversion ratio of common stock at the option of the holder.

+ References

No definition available.

+ Details

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- Definition

There is no established public trading market for our Class B Common Stock, which is held exclusively by members of the Horne family. The principal holders of such stock are subject to restrictions on transfer with respect to their shares. Each share of our Class B Common Stock (10 votes per share) is convertible into one share of Class A Common Stock (1 vote per share).

+ References

No definition available.

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Common Stock (Details) (USD $) In Millions, except Share data, unless otherwise specified	0 Months Ended	12 Months Ended		1 Months Ended
	Jul. 31, 2012	Dec. 31, 2014	Dec. 31, 2013	Jul. 31, 2012	Apr. 30, 2013	May 16, 2012
Common Stock
Common Stock conversion ratio, at the option of the holder		1wts_CommonStockOptionalConversionRatio
Options to purchase shares of Class A common stock					$ 90.0
Number of shares authorized to be repurchased						2,000,000
Number of shares repurchased	2,000,000	670,000	454,000
Cost of shares of Class A common stock repurchased	65.8	39.6	23.0
Class A
Common Stock
Common Stock, votes per share (Number of votes)		1	1
Shares of Common Stock reserved for issuance under stock-based compensation plans		28,552,065
Options to purchase shares of Class A common stock					90.0
Number of shares authorized to be repurchased						2,000,000
Number of shares repurchased		670,000	454,000	2,000,000
Cost of shares of Class A common stock repurchased		$ 39.6	$ 23.0	$ 65.8
Class B
Common Stock
Common Stock, votes per share (Number of votes)		10	10
Shares of Common Stock reserved for conversion		6,479,290