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Debt (Schedule of Additional Information Related to Debt Instruments) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Revolving Secured Line of Credit [Member]
Debt Instrument [Line Items]
Maximum outstanding balance	$ 123.7	$ 51.2	$ 186.4	$ 206.3
Average outstanding balance	22.2	6.9	39.4	57.1
Warehouse Facility II [Member]
Debt Instrument [Line Items]
Maximum outstanding balance	200.1	0.0	200.1	190.0
Average outstanding balance	6.6	0.0	5.5	13.8
Warehouse Facility IV [Member]
Debt Instrument [Line Items]
Maximum outstanding balance	12.0	12.0	12.0	35.0
Average outstanding balance	12.0	6.2	12.0	6.3
Warehouse Facility V [Member]
Debt Instrument [Line Items]
Maximum outstanding balance	100.0	29.0	100.0	75.0
Average outstanding balance	3.3	24.3	2.1	19.8
Warehouse Facility VI [Member]
Debt Instrument [Line Items]
Maximum outstanding balance	49.9	0.0	49.9	0.0
Average outstanding balance	$ 1.6	$ 0.0	$ 6.0	$ 0.0

X

- Definition

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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No definition available.

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- Definition

Average amount borrowed under the credit facility during the period.

+ References

No definition available.

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X

- Definition

Maximum amount borrowed under the credit facility at any time during the period.

+ References

No definition available.

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- Details

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