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-Topic 235
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-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

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The percentage rate used to calculate dividend payments on preferred stock.

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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.

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Related Party Transactions - Narrative (Details) - USD ($) $ in Millions		3 Months Ended		9 Months Ended		12 Months Ended
	Jun. 26, 2019	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018
Related Party Transaction [Line Items]
Long-term debt, related party		$ 0.0		$ 0.0		$ 105.0
Interest expense, related party		0.0	$ 3.6	7.2	$ 5.8
A&R MPSA Services
Related Party Transaction [Line Items]
Due to related parties		$ 0.7		$ 0.7		0.8
Related Party
Related Party Transaction [Line Items]
Long-term debt, related party						$ 105.0
Repayment of subordinated notes, prepayment penalty amount	$ 2.2
Redeemable Convertible Preferred Stock
Related Party Transaction [Line Items]
Preferred stock, dividend rate, percentage				8.00%		8.00%
TCP-ASC ACHI Series LLLP \| Redeemable Convertible Preferred Stock \| Related Party
Related Party Transaction [Line Items]
Preferred stock, dividend rate, percentage				8.00%