Including the current and noncurrent portions, carrying value as of the balance sheet date of a written promise to pay a note, initially due after one year or beyond the operating cycle if longer, which can be exchanged for a specified amount of one or more securities (typically common stock), at the option of the issuer or the holder.

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Ratio applied to the conversion of debt instrument into equity with equity shares divided by debt principal amount.

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Face (par) amount of debt instrument at time of issuance.

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Contractual interest rate for funds borrowed, under the debt agreement.

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The amount of debt discount that was originally recognized at the issuance of the instrument that has yet to be amortized.

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The fair value amount of long-term debt whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission.

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Other Debt - Convertible Senior Note Offering (Details) (USD $)				6 Months Ended				6 Months Ended
	Jun. 30, 2014	Dec. 31, 2013	Jul. 29, 2013 Convertible Senior Note [Member] Convertible Senior Notes [Member]	Jun. 30, 2014 Original 2018 Notes [Member] Convertible Senior Notes [Member]	Aug. 01, 2013 Original 2018 Notes [Member] Convertible Senior Notes [Member]	Jun. 30, 2014 Reopened 2018 Notes [Member] Convertible Senior Notes [Member]	Dec. 10, 2013 Reopened 2018 Notes [Member] Convertible Senior Notes [Member]	Jun. 30, 2014 2020 Notes [Member] Convertible Senior Notes [Member]	Dec. 10, 2013 2020 Notes [Member] Convertible Senior Notes [Member]
Debt Instrument [Line Items]
Proceeds from issuance of convertible debt			$ 300,000,000		$ 10,000,000		$ 287,500,000		$ 402,500,000
Long-term debt, fair value				301,500,000	299,600,000	282,700,000	282,100,000		389,700,000
Debt instrument, unamortized discount					10,400,000		5,400,000	25,000,000	12,800,000
Debt instrument, interest rate, stated percentage									3.75%
Convertible senior note	$ 975,003,000	$ 972,490,000						$ 390,700,000
Debt Instrument, Convertible, Conversion Ratio				0.059805				0.0660262