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Derivatives - NSM Interest Rate Swap (Details) - USD ($) $ in Millions	3 Months Ended		8 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2018	Dec. 31, 2019	Jun. 15, 2018
Derivative [Line Items]
Debt	$ 294.7			$ 283.5
NSM Holding Co LLC
Derivative [Line Items]
Debt	218.4			219.2
NSM Holding Co LLC | NSM Bank Facility
Derivative [Line Items]
Debt	217.1			217.4
Term Loan | NSM Holding Co LLC | NSM Bank Facility
Derivative [Line Items]
Debt	$ 220.7
Interest Rate Swap | NSM Holding Co LLC
Derivative [Line Items]
Derivative, fixed interest rate					2.97%
Derivative, variable interest rate	1.58%
Interest expense, net	$ 0.5	$ 0.2
Derivative, fair value, net	9.8			$ 6.6
Change in fair value of derivative	$ (3.2)	$ (1.9)
Interest Rate Swap | Term Loan | NSM Holding Co LLC | NSM Bank Facility
Derivative [Line Items]
Total commitment under revolving credit facility					$ 151.0
Derivative, fixed interest rate	2.97%
Debt	$ 148.4
Debt, weighted average interest rate, all-in	6.34%
Margin over London Interbank Offered Rate (LIBOR) | Minimum | Term Loan | NSM Holding Co LLC | NSM Bank Facility
Derivative [Line Items]
Basis spread on variable rate	4.25%		4.25%
Margin over London Interbank Offered Rate (LIBOR) | Maximum | Term Loan | NSM Holding Co LLC | NSM Bank Facility
Derivative [Line Items]
Basis spread on variable rate	4.75%		4.75%
Margin over Prime Rate | Minimum | Term Loan | NSM Holding Co LLC | NSM Bank Facility
Derivative [Line Items]
Basis spread on variable rate	3.25%		3.25%
Margin over Prime Rate | Maximum | Term Loan | NSM Holding Co LLC | NSM Bank Facility
Derivative [Line Items]
Basis spread on variable rate	3.75%		3.75%
Designated as Hedging Instrument | Interest Rate Swap | Term Loan | NSM Holding Co LLC | NSM Bank Facility
Derivative [Line Items]
Debt	$ 148.4
Debt, weighted average interest rate, all-in	7.47%

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- Definition

Amount of gain (loss) from the increase (decrease) in fair value of derivative and nonderivative instruments designated as fair value hedging instruments recognized in the income statement.

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Fair value of the assets less the liabilities of a derivative or group of derivatives.

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Fixed interest rate related to the interest rate derivative.

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Variable interest rate in effect as of the balance sheet date related to the interest rate derivative.

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Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

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Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

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