Income Taxes - Tax Credit Carryforward (Details) - USD ($) $ in Millions	Jun. 30, 2021	Dec. 31, 2020
Income Taxes
Income tax payable	$ 2.6	$ 2.7

Carrying amount as of the balance sheet date of the unpaid sum of the known and estimated amounts payable to satisfy all domestic and foreign income tax obligations due. This amount is the total of current and noncurrent accrued income taxes.

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Name:	us-gaap_AccruedIncomeTaxes
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant