Information on Business Segments (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2020 USD ($) Segment	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)
Segment Reporting Information [Line Items]
Number of reportable segments | Segment	2
Revenues	$ 1,124,391	$ 1,491,118	$ 1,495,889
Operating profit	123,370	236,448	231,764
Assets	2,676,226	2,738,335	2,809,000
Depreciation and amortization	87,656	99,059	94,238
Capital expenditures	40,698	53,286	57,273
Interest expense	15,944	20,629	16,841
Other expense (income), net	5,931	8,975	7,428
Income before income taxes	$ 101,495	$ 206,844	$ 207,495
General Electric [Member]
Segment Reporting Information [Line Items]
Revenue by major customer	17.00%	21.00%	18.00%
Industrial [Member]
Segment Reporting Information [Line Items]
Revenues	$ 770,119	$ 938,507	$ 994,727
Operating profit	66,600	114,000	130,400
Assets	1,908,400	1,879,300	1,962,400
Depreciation and amortization	57,700	62,400	57,600
Capital expenditures	19,400	25,300	33,400
Aerospace [Member]
Segment Reporting Information [Line Items]
Revenues	354,272	552,611	501,162
Operating profit	56,800	122,500	101,400
Assets	623,500	704,300	692,600
Depreciation and amortization	29,000	35,900	35,900
Capital expenditures	20,800	26,000	23,600
Other [Member]
Segment Reporting Information [Line Items]
Revenues	0	0	0
Operating profit	0	0	0
Assets	144,300	154,800	154,000
Depreciation and amortization	900	800	800
Capital expenditures	$ 500	$ 2,000	$ 300