Debt and Credit Facility, Additional Information Regarding Convertible Notes (Details) - Convertible Notes Payable - Convertible Notes - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2015	Dec. 31, 2014
Debt Instrument
Contractual coupon interest	$ 2.0	$ 7.9
Amortization of discount	2.4	9.1
Amortization of debt issuance costs	0.3	1.1
Total interest expense	$ 4.7	$ 18.1

Amount of noncash expense included in interest expense to amortize debt discount and premium associated with the related debt instruments. Excludes amortization of financing costs. Alternate captions include noncash interest expense.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
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-Publisher FASB
-Name Accounting Standards Codification
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Reference 3: http://www.xbrl.org/2003/role/presentationRef
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-Name Accounting Standards Codification
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-Section S99
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Amount of amortization expense attributable to debt issuance costs.

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