Other Non-Operating Income (Expense), Net (Details) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2019	Dec. 31, 2018		Dec. 31, 2017
Other Non-Operating Income (Expense), Net [Abstract]
Interest and dividend income			$ 97	$ 80		$ 91
Equity income (loss) from joint ventures			2,865	(768)	[1]	(602)	[1]
Gain (loss) on foreign exchange			(502)	(120)		950
Postretirement plan net periodic benefit credit (cost)			25	262		653
Other non-operating income, net			102	135		158
Total other non-operating income (expense), net			$ 2,587	(411)		1,250
Orange Electronic Co., Ltd [Member]
Asset Impairment Charges [Abstract]
Impairment charges	$ 1,700	$ 1,800		$ 1,700		$ 1,800

[1] Year ended December 31, 2018 and 2017 includes a noncash impairment charge of approximately $1.7 million and $1.8 million, respectively, related to our minority interest investment in Orange Electronic Co., Ltd.  (See Note 10, “Investments in Unconsolidated Affiliates” for additional information).