Nominal or face amount used to calculate payments on the derivative asset.

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Derivative Financial Instruments - Derivative Instruments (Details) - USD ($) $ in Millions	2 Months Ended	7 Months Ended	12 Months Ended
	Sep. 30, 2018	Jul. 31, 2018	Dec. 31, 2017
Derivatives, Fair Value [Line Items]
Derivative instruments at fair value, less than	$ 0.1
Derivative Assets \| Loan sale commitments
Derivatives, Fair Value [Line Items]
Outstanding Notional - Asset	428.0
Fair Value - Asset	6.9
Recorded Gains / (Losses)	(3.7)
Derivative Assets \| IRLCs
Derivatives, Fair Value [Line Items]
Outstanding Notional - Asset	1,765.0
Fair Value - Asset	57.8
Recorded Gains / (Losses)	(1.8)
Derivative Assets \| Forward sales of MBS
Derivatives, Fair Value [Line Items]
Outstanding Notional - Asset	3,040.0
Fair Value - Asset	12.2
Recorded Gains / (Losses)	9.0
Derivative Assets \| LPCs
Derivatives, Fair Value [Line Items]
Outstanding Notional - Asset	228.0
Fair Value - Asset	1.7
Recorded Gains / (Losses)	0.5
Derivative Assets \| Treasury futures
Derivatives, Fair Value [Line Items]
Outstanding Notional - Asset	65.0
Fair Value - Asset	0.0
Recorded Gains / (Losses)	0.0
Derivative Assets \| Eurodollar futures
Derivatives, Fair Value [Line Items]
Outstanding Notional - Asset	20.0
Fair Value - Asset	0.0
Recorded Gains / (Losses)	0.0
Derivative Liabilities \| IRLCs
Derivatives, Fair Value [Line Items]
Outstanding Notional - Liability	3.0
Fair Value - Liability	0.0
Recorded Gains / (Losses)	0.0
Derivative Liabilities \| Forward sales of MBS
Derivatives, Fair Value [Line Items]
Outstanding Notional - Liability	413.0
Fair Value - Liability	0.5
Recorded Gains / (Losses)	(1.4)
Derivative Liabilities \| LPCs
Derivatives, Fair Value [Line Items]
Outstanding Notional - Liability	320.0
Fair Value - Liability	1.5
Recorded Gains / (Losses)	0.9
Derivative Liabilities \| Treasury futures
Derivatives, Fair Value [Line Items]
Outstanding Notional - Liability	53.0
Fair Value - Liability	0.1
Recorded Gains / (Losses)	0.1
Derivative Liabilities \| Eurodollar futures
Derivatives, Fair Value [Line Items]
Outstanding Notional - Liability	6.0
Fair Value - Liability	0.0
Recorded Gains / (Losses)	$ 0.0
Predecessor
Derivatives, Fair Value [Line Items]
Derivative instruments at fair value, less than			$ 0.1
Predecessor \| Derivative Assets \| Loan sale commitments
Derivatives, Fair Value [Line Items]
Outstanding Notional - Asset			1.0
Fair Value - Asset			0.1
Recorded Gains / (Losses)		$ 10.5	0.0
Predecessor \| Derivative Assets \| IRLCs
Derivatives, Fair Value [Line Items]
Outstanding Notional - Asset			2,531.0
Fair Value - Asset			68.7
Recorded Gains / (Losses)		0.4	(23.5)
Predecessor \| Derivative Assets \| Forward sales of MBS
Derivatives, Fair Value [Line Items]
Outstanding Notional - Asset			2,524.0
Fair Value - Asset			4.7
Recorded Gains / (Losses)		0.9	(34.5)
Predecessor \| Derivative Assets \| LPCs
Derivatives, Fair Value [Line Items]
Outstanding Notional - Asset			132.0
Fair Value - Asset			1.0
Recorded Gains / (Losses)		0.3	(0.9)
Predecessor \| Derivative Assets \| Treasury futures
Derivatives, Fair Value [Line Items]
Outstanding Notional - Asset			255.0
Fair Value - Asset			2.0
Recorded Gains / (Losses)		(1.8)	2.0
Predecessor \| Derivative Assets \| Eurodollar futures
Derivatives, Fair Value [Line Items]
Outstanding Notional - Asset			11.0
Fair Value - Asset			0.0
Recorded Gains / (Losses)		0.0	0.0
Predecessor \| Derivative Assets \| Interest rate swaps
Derivatives, Fair Value [Line Items]
Outstanding Notional - Asset			0.0
Fair Value - Asset			0.0
Recorded Gains / (Losses)			(0.1)
Predecessor \| Derivative Liabilities \| IRLCs
Derivatives, Fair Value [Line Items]
Outstanding Notional - Liability			7.0
Fair Value - Liability			0.0
Recorded Gains / (Losses)		0.0	1.1
Predecessor \| Derivative Liabilities \| Forward sales of MBS
Derivatives, Fair Value [Line Items]
Outstanding Notional - Liability			1,137.0
Fair Value - Liability			3.2
Recorded Gains / (Losses)		(1.0)	6.8
Predecessor \| Derivative Liabilities \| LPCs
Derivatives, Fair Value [Line Items]
Outstanding Notional - Liability			335.0
Fair Value - Liability			1.2
Recorded Gains / (Losses)		0.1	0.3
Predecessor \| Derivative Liabilities \| Treasury futures
Derivatives, Fair Value [Line Items]
Outstanding Notional - Liability			479.0
Fair Value - Liability			2.0
Recorded Gains / (Losses)		(1.3)	(2.0)
Predecessor \| Derivative Liabilities \| Eurodollar futures
Derivatives, Fair Value [Line Items]
Outstanding Notional - Liability			45.0
Fair Value - Liability			0.0
Recorded Gains / (Losses)		$ 0.0	0.0
Predecessor \| Derivative Liabilities \| Interest rate swaps
Derivatives, Fair Value [Line Items]
Outstanding Notional - Liability			0.0
Fair Value - Liability			0.0
Recorded Gains / (Losses)			$ 0.1