Contingencies (Schedule of Changes in Claims) (Details) - Asbestos Litigation [Member] $ in Thousands	6 Months Ended	12 Months Ended
	Jun. 30, 2019 USD ($) claims	Dec. 31, 2018 USD ($) claims	Dec. 31, 2017 USD ($) claims	Dec. 31, 2016 USD ($) claims	Dec. 31, 2015 USD ($) claims	Dec. 31, 2014 USD ($) claims
Loss Contingencies [Line Items]
Opening Number of Claims	3,684	3,730	3,745	3,791	3,821	4,299
Claims Dismissed, Settled, or Resolved	24	152	105	148	116	625
New Claims	31	106	90	102	86	147
Closing Number of Claims	3,691	3,684	3,730	3,745	3,791	3,821
Amounts Paid (thousands) to Settle or Resolve | $		$ 100	$ 55	$ 758	$ 164	$ 437