Income Taxes - Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Deferred tax assets (liabilities)
Deferred revenue	$ 20.1	$ 26.9
Warranty reserves	4.7	7.1
Inventory reserves	8.7	12.1
Allowance for doubtful accounts	3.7	4.5
Employee benefits	31.3	45.2
Foreign loss carryforwards	3.8	2.9
Federal tax credit carryovers	3.1
Deferred state tax attributes	13.6	14.6
Other, net	2.4	7.0
Gross deferred assets	91.4	126.9
Valuation allowances	(4.3)	(1.3)
Deferred tax assets after valuation allowances	87.1	125.6
Undistributed foreign earnings	(7.9)	(1.7)
Depreciation	(42.7)	(42.4)
Amortization	(47.3)	(60.7)
Acquired identifiable intangibles	(188.3)	(134.7)
Gross deferred liabilities	(286.2)	(239.5)
Net deferred tax liabilities	(199.1)	(113.9)
Deferred tax assets, federal NOL	0.0	$ 6.6
Deferred tax asset for state tax loss carry forwards	9.5
Valuation allowance on state tax losses	$ 1.2