Equity - Accumulated Other Comprehensive Income, Net of Tax (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Accumulated Other Comprehensive Income, Net of Tax [Roll Forward]
Reclassification of tax effects upon adoption of ASU 2018-02 (Topic 220), net		$ 0.0
Accumulated Other Comprehensive Loss
Accumulated Other Comprehensive Income, Net of Tax [Roll Forward]
Balance at beginning of period	$ (18.2)	(5.4)	$ (37.3)
Other comprehensive income (loss) before reclassifications	(5.4)	(18.2)	39.2
Amount reclassified from accumulated other comprehensive income (loss)	5.1	(0.3)	(7.3)
Other comprehensive income (loss), net	(0.3)	(18.5)	31.9
Reclassification of tax effects upon adoption of ASU 2018-02 (Topic 220), net		5.7
Balance at end of period	(18.5)	(18.2)	(5.4)
Unrealized Gains on Available-for- Sale Securities
Accumulated Other Comprehensive Income, Net of Tax [Roll Forward]
Balance at beginning of period	25.5	19.0	16.6
Other comprehensive income (loss) before reclassifications	4.6	0.6	4.5
Amount reclassified from accumulated other comprehensive income (loss)	(0.4)	0.9	(2.1)
Other comprehensive income (loss), net	4.2	1.5	2.4
Reclassification of tax effects upon adoption of ASU 2018-02 (Topic 220), net		5.0
Balance at end of period	29.7	25.5	19.0
Unrealized Losses on Cash Flow Hedges
Accumulated Other Comprehensive Income, Net of Tax [Roll Forward]
Balance at beginning of period	(0.9)	6.0	(4.5)
Other comprehensive income (loss) before reclassifications	(8.9)	(6.4)	15.7
Amount reclassified from accumulated other comprehensive income (loss)	5.5	(1.2)	(5.2)
Other comprehensive income (loss), net	(3.4)	(7.6)	10.5
Reclassification of tax effects upon adoption of ASU 2018-02 (Topic 220), net		0.7
Balance at end of period	(4.3)	(0.9)	6.0
Foreign Currency Translation Adjustments
Accumulated Other Comprehensive Income, Net of Tax [Roll Forward]
Balance at beginning of period	(42.8)	(30.4)	(49.4)
Other comprehensive income (loss) before reclassifications	(1.1)	(12.4)	19.0
Amount reclassified from accumulated other comprehensive income (loss)	0.0	0.0	0.0
Other comprehensive income (loss), net	(1.1)	(12.4)	19.0
Reclassification of tax effects upon adoption of ASU 2018-02 (Topic 220), net		0.0
Balance at end of period	$ (43.9)	$ (42.8)	$ (30.4)

Accumulated Other Comprehensive Income, Net of Tax [Roll Forward]

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Amount after tax, before reclassification adjustments, of other comprehensive income (loss), attributable to parent.

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Amount after tax of other comprehensive income (loss) attributable to parent entity.

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Amount after tax of reclassification adjustments of other comprehensive income (loss) attributable to parent.

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Total of all stockholders' equity (deficit) items, net of receivables from officers, directors, owners, and affiliates of the entity which are attributable to the parent. The amount of the economic entity's stockholders' equity attributable to the parent excludes the amount of stockholders' equity which is allocable to that ownership interest in subsidiary equity which is not attributable to the parent (noncontrolling interest, minority interest). This excludes temporary equity and is sometimes called permanent equity.

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Amount of increase (decrease) in accumulated other comprehensive income (AOCI) for reclassification to retained earnings of tax effect from remeasurement of deferred tax pursuant to Tax Cuts and Jobs Act.

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