Income Taxes - Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2015	Dec. 31, 2014
Deferred tax assets:
Accounts receivable		$ 3.9
Accrued expenses	$ 5.3	6.7
Compensation	26.9	27.9
Deferred revenue		0.4
Net operating loss carryforwards	24.3	19.1
Fixed assets	3.9
Inventory		2.8
Foreign tax and other tax credit carryforwards	8.3	5.9
Unrealized currency gain/loss	1.1	3.2
Gross deferred tax assets	69.8	69.9
Less valuation allowance	(4.3)		$ (0.5)	$ (37.2)
Total deferred tax assets	65.5	69.9
Deferred tax liabilities:
Accounts receivable	1.2
Investments	0.5
Inventory	1.8
Deferred revenue	5.9
Fixed assets		0.3
Foreign statutory reserves	0.4	0.9
Intangibles	47.6	13.0
Accrued expenses	0.3	0.6
Accrued withholding tax	4.8	16.1
Other	3.2	6.4
Total deferred tax liabilities	65.7	37.3
Net deferred tax assets	$ 0.2	$ 32.6