Income Taxes (Effective Income Tax Rate Reconciliation) (Details)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Effective Income Tax Rate, Continuing Operations, Tax Rate Reconciliation [Abstract]
Tax provision at statutory rate based on income before income taxes (percent)	35.00%	35.00%	35.00%
Effective Income Tax Rate Reconciliation Tax Reform	(111.00%)	0.00%	0.00%
Effective Income Tax Rate Reconciliation, Consolidated Group Restructuring	(7.40%)	0.00%	0.00%
Foreign income taxes (percent)	(5.30%)	(6.80%)	(3.60%)
Federal research credit (percent)	(2.80%)	(5.60%)	(2.00%)
Settlement of taxing authority examinations (percent)	(2.10%)	(3.50%)	(0.60%)
Stock-based compensation (percent)	(2.10%)	(0.00%)	(0.00%)
European permanent deduction (percent)	(0.50%)	(3.40%)	(2.10%)
Non deductible/non-taxable items (percent)	(0.50%)	7.20%	1.80%
State income taxes, net of federal tax benefit (percent)	2.80%	1.70%	3.20%
Impact of repatriation of foreign earnings (percent)	0.00%	0.00%	2.50%
Other, net (percent)	0.80%	(0.30%)	(1.80%)
Effective income tax rate, continuing operations (percent)	(93.10%)	24.30%	32.40%