Represents the percentage of original issuance discount.

No definition available.

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- Definition

Amount of noncash expense included in interest expense to allocate debt discount and premium, and the costs to issue debt and obtain financing over the related debt instruments. Alternate captions include noncash interest expense.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-URI http://asc.fasb.org/extlink&oid=56944662&loc=d3e3602-108585

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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
-Topic 835
-SubTopic 30
-Section 55
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- Definition

Effective interest rate for the funds borrowed under the debt agreement considering interest compounding and original issue discount or premium.

+ 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(a)(1))
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- Definition

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

+ References

+ Details

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- Definition

Percentage price of original principal amount of debt at which debt can be redeemed by the issuer.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 470
-Section 50
-Paragraph 3
-Subparagraph e
-URI http://asc.fasb.org/extlink&oid=6479336&loc=d3e64711-112823

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- Definition

Face (par) amount of the original debt instrument that was repurchased.

+ References

No definition available.

+ Details

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Balance Type:	debit
Period Type:	instant

- Definition

Amount of the cost of borrowed funds accounted for as interest expense for debt.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 225
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03.8)
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- References

No definition available.

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- Definition

Represents the portion of interest incurred in the period on debt arrangements that was charged against earnings, excluding amortization of debt discount (premium) and financing costs.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 225
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph 8
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- References

No definition available.

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- Definition

The cash inflow from additional borrowings, net of cash paid to third parties in connection with debt origination.

+ References

No definition available.

+ Details

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- Definition

The cash outflow from the repayment of a long-term debt instrument which can be exchanged for a specified amount of another security, typically the entity's common stock, at the option of the issuer or the holder.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Financing Activities
-URI http://asc.fasb.org/extlink&oid=6513228

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Long-term debt: Convertible senior notes (Details) - USD ($) $ in Thousands			1 Months Ended	12 Months Ended
	Jun. 20, 2014	Jun. 16, 2014	Jun. 30, 2007	Dec. 31, 2016	Dec. 31, 2014	Dec. 31, 2008
Convertible senior notes
Purchase of convertible notes in cash					$ 91,978
Convertible senior notes
Convertible senior notes
Interest rate (as a percent)			1.00%
Proceeds from issuance of long-term debt, net of issuance costs			$ 195,100
Percentage of original issuance discount			2.25%
Aggregate principal amount of debt issued			$ 200,000
Purchase of convertible notes in cash	$ 33,500	$ 58,500				$ 48,600
Aggregate face value of debt repurchased						$ 108,000
Amount of interest expense recognized and effective interest rate
Contractual coupon interest					419
Amortization of discount and costs on Notes					3,106
Interest expense					$ 3,525
Effective interest rate (as a percent)					8.70%
June 15, 2014, 2017 and 2022 \| Convertible senior notes
Convertible senior notes
Percentage of principal amount that the holders of the Convertible Notes may require the Company to repurchase				100.00%
After June 20, 2014 \| Convertible senior notes
Convertible senior notes
Percentage of principal amount that the holders of the Convertible Notes may require the Company to repurchase				100.00%