Income Taxes - Deferred Income Tax Assets and Liabilities (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Deferred tax assets:
Property, plant and equipment	$ 1.7	$ 1.7
Accrued expenses	24.0	31.8
Stock based compensation	2.6	3.6
Net operating loss, research and development and foreign tax credit carryforwards	22.6	22.6
Goodwill and intangibles	0.4	1.2
Pension benefits	22.7	32.9
Other	0.8	0.1
Gross deferred tax assets	74.8	93.9
Valuation allowance	(10.6)	(7.7)
Total deferred tax assets	64.2	86.2
Deferred tax liabilities:
Property, plant and equipment	(11.3)	(10.5)
Pension benefits	(13.5)	(14.5)
Goodwill and intangibles	(77.1)	(51.1)
Other	(1.2)	(1.6)
Gross deferred tax liabilities	(103.1)	(77.7)
Net deferred tax (liabilities) assets	$ (38.9)	$ 8.5