Income Taxes - Effective income tax rate reconciliation (Details)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 21, 2017	Dec. 31, 2016
Income Tax Disclosure [Abstract]
Statutory U.S. federal income tax rate	21.00%	35.00%	35.00%	35.00%
State and local taxes, net of federal income tax benefit	3.30%	2.10%		(3.90%)
Foreign derived intangible income	(1.90%)
Foreign operations tax effect	0.80%	(2.80%)		7.80%
Research and experimentation tax credits	(0.60%)	(0.70%)		2.30%
Domestic manufacturing deduction		(4.40%)		6.20%
Nondeductible expenses	0.70%	0.70%		(3.30%)
ESOP dividends	(0.10%)	(0.20%)		2.90%
Branch income		1.10%		(2.90%)
Changes due to the Tax Reform Act		(54.30%)
Other	0.20%	(0.60%)		(1.60%)
Effective income tax rate	23.40%	(24.10%)		42.50%