Other (Income) Expense, Net (Foreign Currency (Gain) Loss by Currency) (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Foreign exchange	$ 654,000	$ 358,000	$ 1,086,000	$ 455,000
Angola, Kwanza
Foreign exchange	57,000	(4,000)	161,000	(3,000)
AustralianDollar [Member]
Foreign exchange	32,000	18,000	110,000	13,000
British Pound
Foreign exchange	104,000	(74,000)	(23,000)	(55,000)
Canadian Dollar
Foreign exchange	243,000	(58,000)	357,000	(77,000)
Euro
Foreign exchange	(259,000)	732,000	(16,000)	835,000
Other Currencies Net [Member]
Foreign exchange	335,000	(261,000)	319,000	(233,000)
Indonesian Rupiah [Member]
Foreign exchange	$ 142,000	$ 5,000	$ 178,000	$ (25,000)