Income Taxes - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Sep. 30, 2018
Income Tax Disclosure [Abstract]
Reductions in unrecognized tax benefits from expiration	$ 0.3	$ 0.7
Benefit related to re-measurement of deferred tax liabilities	$ 0.7
U.S. statutory federal tax rate (as a percent)	35.00%		21.00%
Cumulative effect adjustment to retained earnings	$ 4.0
Toll charge, payable period	8 years
Toll charge, estimated foreign earnings	$ 120.0
U.S. statutory federal tax rate, prorated allocation (as a percent)	24.50%
Anticipated unrecognized tax benefit reduction during next twelve months	$ 0.2