Revenues Revenues (Disaggregation of Revenue by Geographic Location) (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 28, 2019	Jun. 29, 2019	Mar. 30, 2019	Dec. 31, 2018	Sep. 29, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Disaggregation of Revenue [Line Items]
Revenue	$ 69,142	$ 67,421	$ 70,870	$ 76,525	$ 76,982	$ 75,490	$ 74,231	$ 73,091	$ 283,958	$ 299,794	$ 254,350
United States
Disaggregation of Revenue [Line Items]
Revenue									114,315	124,905	105,663
United Kingdom
Disaggregation of Revenue [Line Items]
Revenue									29,207	29,749	26,487
Other Europe
Disaggregation of Revenue [Line Items]
Revenue									59,999	60,850	52,427
Israel
Disaggregation of Revenue [Line Items]
Revenue									12,816	11,545	7,308
Asia
Disaggregation of Revenue [Line Items]
Revenue									44,817	51,443	45,084
Canada
Disaggregation of Revenue [Line Items]
Revenue									22,804	21,302	17,381
Foil Technology Products
Disaggregation of Revenue [Line Items]
Revenue									131,803	141,009	116,273
Foil Technology Products | United States
Disaggregation of Revenue [Line Items]
Revenue									56,393	61,132	52,032
Foil Technology Products | United Kingdom
Disaggregation of Revenue [Line Items]
Revenue									3,181	3,666	3,173
Foil Technology Products | Other Europe
Disaggregation of Revenue [Line Items]
Revenue									32,328	31,431	26,322
Foil Technology Products | Israel
Disaggregation of Revenue [Line Items]
Revenue									12,401	11,028	6,673
Foil Technology Products | Asia
Disaggregation of Revenue [Line Items]
Revenue									27,500	33,752	28,073
Foil Technology Products | Canada
Disaggregation of Revenue [Line Items]
Revenue									0	0	0
Force Sensors
Disaggregation of Revenue [Line Items]
Revenue									64,357	73,186	65,446
Force Sensors | United States
Disaggregation of Revenue [Line Items]
Revenue									33,695	39,955	34,108
Force Sensors | United Kingdom
Disaggregation of Revenue [Line Items]
Revenue									10,450	11,787	12,187
Force Sensors | Other Europe
Disaggregation of Revenue [Line Items]
Revenue									10,811	10,678	8,793
Force Sensors | Israel
Disaggregation of Revenue [Line Items]
Revenue									415	517	635
Force Sensors | Asia
Disaggregation of Revenue [Line Items]
Revenue									8,986	10,249	9,723
Force Sensors | Canada
Disaggregation of Revenue [Line Items]
Revenue									0	0	0
Weighing and Control Systems
Disaggregation of Revenue [Line Items]
Revenue									87,798	85,599	72,631
Weighing and Control Systems | United States
Disaggregation of Revenue [Line Items]
Revenue									24,227	23,818	19,523
Weighing and Control Systems | United Kingdom
Disaggregation of Revenue [Line Items]
Revenue									15,576	14,296	11,127
Weighing and Control Systems | Other Europe
Disaggregation of Revenue [Line Items]
Revenue									16,860	18,741	17,312
Weighing and Control Systems | Israel
Disaggregation of Revenue [Line Items]
Revenue									0	0	0
Weighing and Control Systems | Asia
Disaggregation of Revenue [Line Items]
Revenue									8,331	7,442	7,288
Weighing and Control Systems | Canada
Disaggregation of Revenue [Line Items]
Revenue									$ 22,804	$ 21,302	$ 17,381