Annual report pursuant to Section 13 and 15(d)

Inventories - Narrative (Details)

v3.19.3.a.u2
Inventories - Narrative (Details) - USD ($)
$ in Thousands
Dec. 31, 2019
Dec. 31, 2018
Inventory [Line Items]    
Reserve for inventory valuation $ 33,600 $ 20,800
Percentage of reserve for inventory valuation 18.70% 12.00%
Held for Sale | Test Systems    
Inventory [Line Items]    
Inventories   $ 14,385