Income Taxes - Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Deferred tax assets:
Accrued expenses	$ 4.7	$ 7.5
Compensation	32.3	32.6
Deferred revenue	13.9	8.4
Disallowed interest carryforward	5.0	2.9
Net operating loss carryforwards	31.1	21.2
Foreign tax and other tax credit carryforwards	16.4	11.0
Unrealized currency gain/loss	9.6	6.1
Lease obligations	15.2	16.3
Gross deferred tax assets	128.2	106.0
Less valuation allowance	(6.6)	(4.2)	$ (4.3)	$ 0.0
Total deferred tax assets	121.6	101.8
Deferred tax liabilities:
Accounts receivable	2.7	0.6
Inventory	10.8	13.3
Fixed assets	10.4	4.9
Foreign patent reserves	2.4	2.2
Intangibles	40.2	40.1
Accrued expenses	2.8	0.9
Accrued Withholding tax	6.7	5.2
Right of use asset	14.9	15.6
Other	2.2	7.3
Total deferred tax liabilities	93.1	90.1
Net deferred tax assets	$ 28.5
Net deferred tax liabilities		$ (11.7)