Income Taxes - Deferred Tax Asset/Liability (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018	Jan. 01, 2018
Deferred income tax assets (liabilities)
Net deferred income tax assets	$ 13.4	$ 16.4
Deferred income tax assets (liabilities)
Net deferred income tax liabilities	(12.9)	(14.4)
Retained earnings	268.1	243.2
Undistributed earnings of foreign subsidiaries	48.8	58.4
NOLs
Deferred tax asset related to net operating losses	2.7
Pre-acquisition built-in loss carryforward	7.6
Pre-acquisition built-in carryovers, deferred tax asset	1.6
Alternative minimum tax credit carryovers	0.7
Domestic Tax Authority
Deferred income tax assets (liabilities)
Research and development tax credits	21.5	20.0
Employee benefits	15.9	16.5
Net operating losses and other tax credits	6.4	7.4
Lease liabilities	3.1
Accrued liabilities	2.1	2.3
Interest limitation	0.0	1.7
Inventories		1.0
Other	0.5	0.5
Net deferred income tax assets	13.4	16.4
Deferred income tax assets (liabilities)
Accelerated depreciation	(28.0)	(28.8)
Intangibles	(4.7)	(4.2)
Inventories	(0.6)
Lease right-of-use assets	(2.8)
State and Local Jurisdiction
NOLs
Net operating losses	44.1
Operating loss carryfowards, valuation allowance	0.5	0.5
Foreign Tax Authority
Deferred income tax assets (liabilities)
Employee benefits	7.5	6.3
Lease liabilities	0.7
Deferred income tax assets (liabilities)
Accelerated depreciation	(16.7)	(16.6)
Intangibles	(3.0)	(3.2)
Inventories	(0.9)	(1.0)
Lease right-of-use assets	(0.7)
Net operating losses	0.2	0.2
Other	0.0	(0.1)
Net deferred income tax liabilities	(12.9)	$ (14.4)
Research Tax Credit Carryforward | Domestic Tax Authority
NOLs
R & D credits subject to expiration	21.0
Research Tax Credit Carryforward | State and Local Jurisdiction
NOLs
R & D credits subject to expiration	$ 7.5
Accounting Standards Update 2016-06 | Domestic Tax Authority
Deferred income tax assets (liabilities)
Deferred income tax assets			$ 2.9
Retained earnings			2.9
Accounting Standards Update 2016-06 | Federal Ministry of Finance, Germany
Deferred income tax assets (liabilities)
Prepaid Taxes			3.7
Retained earnings			$ (3.7)