Long-Term Debt Components of Convertible Debt (Details) - USD ($)	9 Months Ended
Sep. 30, 2016	Sep. 30, 2015	Dec. 31, 2015
Debt Instrument [Line Items]
Issuance of warrants	$ 12,376,000	$ 0
Convertible Debt Conversion Feature	20,901,000		$ 0
Convertible note hedge asset	16,678,000		0
Long-term debt	$ 160,094,000		47,120,000
Convertible Subordinated Debt \| Convertible Senior Subordinated Debentures at 4.125% February 2027
Debt Instrument [Line Items]
Interest rate (as a percent)	4.125%
Principal amount of liability component	$ 13,350,000		13,350,000
Unamortized discount	(544,000)		(1,203,000)
Long-term debt	$ 12,806,000		12,147,000
Convertible Subordinated Debt \| Convertible Senior Notes at 5.00% February 2021 [Member]
Debt Instrument [Line Items]
Interest rate (as a percent)	5.00%
Unamortized discount	$ (31,330,000)
Long-term debt	$ 113,450,000		$ 0

Convertible Debt Conversion Feature, Fair Value

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- Definition

Convertible due 2021 - Bond Hedge, Fair Value

+ References

No definition available.

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- Definition

Amount, before unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but is not limited to, notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt.

+ 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(22))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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-Name Accounting Standards Codification
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-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(16))
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

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- Definition

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

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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- Definition

Amount, after accumulated amortization, of debt discount.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 1A
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Amount of long-term debt and capital lease obligations including current maturities.

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- Definition

The cash inflow from issuance of rights to purchase common shares at predetermined price (usually issued together with corporate debt).

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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