Income Taxes, Reconciliation of Statutory to Effective Income Tax Rate (Details) - USD ($) $ in Millions	1 Months Ended		3 Months Ended		12 Months Ended
	Jul. 31, 2017	Jun. 30, 2017	Dec. 31, 2017	Jun. 30, 2017	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Reconciliation of Statutory to Effective Income Tax Rate [Abstract]
Federal statutory rate					35.00%	35.00%	35.00%
State taxes, net of federal benefit					3.30%	3.90%	4.00%
Effect of foreign operations					1.90%	(2.10%)	(2.60%)
Foreign Toll Charge - U.S. tax reform					4.10%	0.00%	0.00%
Stock compensation					1.90%	2.40%	3.40%
Non-deductible acquisition costs					0.00%	0.00%	0.30%
Research and development tax credit					(1.00%)	(5.00%)	(9.00%)
U.S. domestic production deduction					(1.60%)	(1.40%)	(1.00%)
Adjustment to deferred tax rate - U.S. tax reform					(12.30%)	0.00%	0.00%
Other					0.20%	0.10%	(0.20%)
Effective tax rate					31.50%	32.90%	29.90%
Foreign earnings repatriated	$ 4.8	$ 4.8
Taxes on foreign earnings repatriated				$ 2.5
Reversal of taxes on foreign earnings repatriated due to 2017 Tax Act			$ (1.6)
Unremitted earnings of foreign subsidiaries			4.9		$ 4.9
Unrecognized deferred tax liability on unremitted earnings of foreign subsidiaries			$ 0.2		$ 0.2