Debt - Convertible Senior Note (Details) - Convertible debt [Member] - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016	Jul. 31, 2015
Debt Instrument [Line Items]
Principal of convertible senior notes	$ 225,000	$ 225,000	$ 225,000
Contractual Interest Rate	4.00%		4.00%
Unamortized debt discount	$ (15,874)	(18,196)
Unamortized financing costs	(3,348)	(3,894)
Carrying value of convertible senior notes	205,778	202,910
Carrying value of the equity component	23,743	$ 23,743
Equity component of convertible debt issuance costs	$ 700

Equity Component of Convertible Debt Issuance Costs

No definition available.

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- Definition

Including the current and noncurrent portions, carrying amount of debt identified as being convertible into another form of financial instrument (typically the entity's common stock) as of the balance sheet date, which originally required full repayment more than twelve months after issuance or greater than the normal operating cycle of the company.

+ References

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-Publisher FASB
-Name Accounting Standards Codification
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-Paragraph 1
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- Definition

The carrying amount of the equity component of convertible debt which may be settled in cash upon conversion.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
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- Definition

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

+ References

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

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

+ References

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-Publisher FASB
-Name Accounting Standards Codification
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- Definition

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.

+ References

No definition available.

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- Definition

Amount, after accumulated amortization, of debt discount.

+ References

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- Definition

The remaining balance of debt issuance expenses that were capitalized and are being amortized against income over the lives of the respective bond issues. This does not include the amounts capitalized as part of the cost of the utility plant or asset.

+ References

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