Shareholders' Equity - Accumulated Other Comprehensive Income (Details) $ in Millions	9 Months Ended
	Sep. 30, 2017 USD ($)
Summary of the components of accumulated other comprehensive income (loss), net of tax
Balance at beginning of period	$ (75.9)
Balance at end of period	10.5
Accumulated Other Comprehensive Income (Loss)
Summary of the components of accumulated other comprehensive income (loss), net of tax
Balance at beginning of period	(75.9)
Other comprehensive income (loss) before reclassifications	83.5
Amounts reclassified from other comprehensive income (loss), net of tax of $0.4 million	2.9
Net current period other comprehensive income	86.4
Balance at end of period	10.5
Amount from reclassification, tax	0.4
Foreign Currency Translation
Summary of the components of accumulated other comprehensive income (loss), net of tax
Balance at beginning of period	(24.1)
Other comprehensive income (loss) before reclassifications	86.4
Net current period other comprehensive income	86.4
Balance at end of period	62.3
Pension Liability Adjustment
Summary of the components of accumulated other comprehensive income (loss), net of tax
Balance at beginning of period	(51.8)
Other comprehensive income (loss) before reclassifications	(2.9)
Amounts reclassified from other comprehensive income (loss), net of tax of $0.4 million	2.9
Balance at end of period	(51.8)
Amount from reclassification, tax	$ 0.4