Income Taxes - Reconciliation of Statutory to Effective Income Tax Rate (Details)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Effective Income Tax Rate Reconciliation, Percent [Abstract]
Federal statutory rate	21.00%	35.00%	35.00%
State taxes, net of federal benefit	4.50%	3.30%	3.90%
Effect of foreign operations	1.50%	1.90%	(2.10%)
Foreign toll charge - U.S. tax reform	0.00%	4.10%	0.00%
Stock compensation	2.00%	1.90%	2.40%
Non-deductible acquisition costs	0.20%	0.00%	0.00%
Research and development tax credit	(5.00%)	(1.00%)	(5.00%)
U.S. domestic production deduction	(0.10%)	(1.60%)	(1.40%)
Adjustment to deferred tax rate - U.S. tax reform	0.00%	(12.30%)	0.00%
Other	0.00%	0.20%	0.10%
Effective tax rate	24.10%	31.50%	32.90%