Income Taxes - Narratives (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Tax Contingency
Tax benefit from changes in enacted taxes	$ 22.5	$ (1.3)	$ 22.5
Provisional decrease of deferred tax liabilities	(26.9)		(26.9)
Provisional deemed repatriation transition tax	(8.7)	3.8	8.7
Additonal tax benefit as a result of JOBS act analysis		1.8
Additional decrease to deferred tax liabilities as a result of JOBS act analysis		3.1
State net operating loss carryforwards	2.0	0.6	2.0
Total deferred tax assets before valuation allowances	54.7	99.1	54.7
Valuation allowances	26.8	65.2	26.8
Foreign net operating loss carryforwards	11.7	11.2	11.7
Investment tax credit		1.0
Undistributed earnings of foreign subsidiaries		206.9
Tax Cuts and Jobs Act undistributed foreign earnings		200.0
Income taxes paid		13.2	15.4	$ 16.9
Unrecognized tax benefit that would impact tax rate if recognized	0.6	0.1	0.6
Income tax penalties and interest accrued	0.1	0.1	0.1
State and Local Jurisdiction | California Franchise Tax Board
Income Tax Contingency
Total deferred tax assets before valuation allowances		1.1
Valuation allowances		0.6
Foreign Tax Authority
Income Tax Contingency
Total deferred tax assets before valuation allowances		11.2
Valuation allowances		11.1
Foreign net operating loss carryforwards		44.8
DTA operating loss carryforward subject to expiration		44.8
Hudson
Income Tax Contingency
Tax benefit from changes in enacted taxes	1.8
Provisional deemed repatriation transition tax	(8.7)		8.7
Additional tax expense (benefit) related to merger	$ 4.5		$ 4.5
Hudson | Adjustments
Income Tax Contingency
Decrease to federal income taxes		$ 2.5