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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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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Derivatives - NSM Interest Rate Swap (Details) - USD ($)	3 Months Ended	5 Months Ended	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2018	Sep. 30, 2018	May 11, 2018	Dec. 31, 2017
NSM Holding Co LLC \| NSM Bank Facility
Derivative [Line Items]
Total commitment under revolving credit facility				$ 100,000,000
Term Loan \| NSM Holding Co LLC \| NSM Bank Facility
Derivative [Line Items]
Face amount	$ 150,600,000	$ 150,600,000	$ 150,600,000		$ 0
Debt, weighted average interest rate, all-in	6.69%	6.69%	6.69%
Interest Rate Swap \| NSM Holding Co LLC
Derivative [Line Items]
Derivative, fixed interest rate	2.9745%	2.9745%	2.9745%
Derivative, variable interest rate	2.07%	2.07%	2.07%
Interest expense, net	$ 300,000.0	$ 400,000.0
Derivative, fair value, net	100,000.0	$ 100,000.0	$ 100,000.0
Change in fair value of derivative	$ 1,000,000.0		$ (100,000.0)
Interest Rate Swap \| Term Loan \| NSM Bank Facility
Derivative [Line Items]
Derivative, variable interest rate	2.07325%	2.07325%	2.07325%
Interest Rate Swap \| Term Loan \| NSM Holding Co LLC \| NSM Bank Facility
Derivative [Line Items]
Derivative, fixed interest rate	2.9745%	2.9745%	2.9745%
Debt, weighted average interest rate, all-in	7.47%	7.47%	7.47%
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%
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%
Margin over Prime Rate \| Minimum \| Term Loan \| NSM Holding Co LLC \| NSM Bank Facility
Derivative [Line Items]
Basis spread on variable rate	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%