Other Long-Term Obligations - (Details) - USD ($)	Dec. 31, 2019	Dec. 31, 2018	Apr. 23, 2015
Other Liabilities Disclosure [Abstract]
Deferred income taxes	$ 23,376,000	$ 24,681,000
Product liability	13,414,000	13,865,000
Pension	7,006,000	6,670,000
Deferred gain on sale leaseback	5,819,000	6,124,000	$ 7,414,000
Supplemental Executive Retirement Plan liability	5,433,000	5,250,000
Deferred compensation	5,354,000	5,577,000
Uncertain tax obligation including interest	2,612,000	2,140,000
Advance payment on sale of land & buildings	0	3,524,000
Convertible 2022 debt conversion liability	0	2,611,000
Convertible 2021 debt conversion liability	0	1,458,000
Other	3,935,000	3,065,000
Other long-term obligations	$ 66,949,000	$ 74,965,000