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.

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

Fair value portion of debt instrument payable, including, but not limited to, notes payable and loans payable.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
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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
-Topic 210
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No definition available.

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Fair value of financial instruments (Details) - USD ($) $ in Millions	Sep. 30, 2021	Dec. 31, 2020	Oct. 17, 2018
5.00% Convertible Senior Notes due 2048
Financial liabilities
Interest rate (as a percent)	5.00%		5.00%
Level 3 \| 5.00% Convertible Senior Notes due 2048
Financial liabilities
Debt, fair value	$ 0.3	$ 0.3
Debt, carrying value	$ 0.2	19.1
Level 3 \| 5.00% Convertible Senior Third Lien Notes due 2048
Financial liabilities
Debt, fair value		$ 30.0