Derivative Contracts (Details) (Not Designated as Hedging Instrument [Member], USD $) In Thousands, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014
Common stock options/warrants \| Investments, net
Derivatives, Fair Value [Line Items]
Derivative asset, fair value	$ 9,723	$ 6,314
Embedded conversion option \| 2033 Senior Notes, net of discount and estimated fair value of embedded derivatives
Derivatives, Fair Value [Line Items]
Derivative liability, fair value	67,787	65,947
Forward Contracts
Derivatives, Fair Value [Line Items]
Derivative liability, fair value	2,160	944
Forward Contracts \| Gains on forward contracts are recorded in Prepaid expenses and other current assets. Losses on forward contracts are recorded in Accrued expenses.
Derivatives, Fair Value [Line Items]
Derivative liability, fair value	$ 14	$ 36

Fair value, before effects of master netting arrangements, of a financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes assets elected not to be offset. Excludes assets not subject to a master netting arrangement.

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Fair value, before effects of master netting arrangements, of a financial liability or contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes liabilities elected not to be offset. Excludes liabilities not subject to a master netting arrangement.

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