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Net gain on the valuation of contingent value rights.

+ References

No definition available.

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Expected dividends to be paid to holders of the underlying shares or financial instruments (expressed as a percentage of the share or instrument's price).

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 820

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (e)

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Period the instrument, asset or liability is expected to be outstanding, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Measure of dispersion, in percentage terms (for instance, the standard deviation or variance), for a given stock price.

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Interest rate used to find the present value of an amount to be paid or received in the future as an input to measure fair value. For example, but not limited to, weighted average cost of capital (WACC), cost of capital, cost of equity and cost of debt.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

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-Section 50

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Price of a single share of a number of saleable stocks of a company.

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No definition available.

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Fair Value Measurements - Valuation techniques and fair value assumptions (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended			0 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Nov. 06, 2013
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Net gain on the valuation of contingent value rights	$ 0	$ (49,570)	$ 0
Recurring \| Level 3 \| Contingent Value Rights
Observable assumptions:
Price per share of Class A common stock				$ 61.25
Remaining term of CVRs				2 years 8 months 4 days
Unobservable assumptions:
Expected price volatility of Class A common stock (percent)				32.00%
Dividend yield rate (percent)				4.40%
Discount rate (percent)				5.00%