Taxes on Income (Reconciliation of Federal Statutory Income Tax Rate to Effective Income Tax Rate) (Details)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Tax Disclosure [Abstract]
Federal statutory income tax rate	35.00%	35.00%	35.00%
State income taxes, net of federal tax benefit	2.20%	2.40%	2.60%
Equity compensation benefit	(2.40%)	0.00%	0.00%
Other	0.70%	(0.50%)	(1.10%)
Effective income tax rate	35.50%	36.90%	36.50%