Net proceeds from sale of payroll tax credits.

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Basis of Presentation and Accounting Policies - Additional Information (Details) € in Millions, $ in Millions	1 Months Ended				3 Months Ended		9 Months Ended
	Apr. 30, 2019 USD ($)	Apr. 30, 2019 EUR (€)	Apr. 30, 2018 USD ($)	Apr. 30, 2018 EUR (€)	Sep. 30, 2019 USD ($)	Jun. 30, 2019 USD ($)	Sep. 30, 2019 USD ($)
Subsequent Event [Line Items]
Net proceeds from sale of tax credits	$ 103.5	€ 92.0	$ 234.5	€ 190.9
Non-cash goodwill impairment charge					$ 0.0		$ 64.0
Impairment of indefinite-lived intangible assets					$ 0.0
Northern Europe \| Germany
Subsequent Event [Line Items]
Non-cash goodwill impairment charge						$ 60.2
APME \| New Zealand
Subsequent Event [Line Items]
Non-cash goodwill impairment charge						$ 3.8
Goodwill \| Measurement Input Discount Rate \| Minimum
Subsequent Event [Line Items]
Discount rate for goodwill impairment test (as a percent)					0.099		0.099
Goodwill \| Measurement Input Discount Rate \| Maximum
Subsequent Event [Line Items]
Discount rate for goodwill impairment test (as a percent)					0.131		0.131