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v3.19.1

Debt (Schedule of Additional Information Related to Debt Instruments) (Details) - USD ($) $ in Millions | 3 Months Ended
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Mar. 31, 2019 | Mar. 31, 2018
Revolving Secured Line of Credit [Member] |  |
Debt Instrument [Line Items] |  |
Maximum outstanding balance | $ 276.4 | $ 177.5
Average outstanding balance | 88.4 | 39.1
Warehouse Facility II [Member] |  |
Debt Instrument [Line Items] |  |
Maximum outstanding balance | 201.0 | 201.0
Average outstanding balance | 93.0 | 4.5
Warehouse Facility IV [Member] |  |
Debt Instrument [Line Items] |  |
Maximum outstanding balance | 100.0 | 0.0
Average outstanding balance | 4.4 | 0.0
Warehouse Facility V [Member] |  |
Debt Instrument [Line Items] |  |
Maximum outstanding balance | 0.0 | 99.0
Average outstanding balance | 0.0 | 2.2
Warehouse Facility VI [Member] |  |
Debt Instrument [Line Items] |  |
Maximum outstanding balance | 101.5 | 75.0
Average outstanding balance | 2.3 | 1.7
Warehouse Facility VII [Member] |  |
Debt Instrument [Line Items] |  |
Maximum outstanding balance | 0.0 | 125.0
Average outstanding balance | $ 0.0 | $ 2.8

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- 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. + References No definition available. + Details
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- Definition Average amount borrowed under the credit facility during the period. + References No definition available. + Details
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- Details
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- Details
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- Details
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