Segment Information Segment Information (Details) - USD ($) $ in Thousands	3 Months Ended			6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Mar. 31, 2018	Jun. 30, 2019	Jun. 30, 2018
Segment Reporting Information [Line Items]
Net sales	$ 239,370	$ 224,910		$ 460,660	$ 442,010
Operating profit (loss)	31,110	31,520		56,960	66,730
Operating Segments [Member] | Packaging [Member]
Segment Reporting Information [Line Items]
Net sales	103,990	95,090		192,830	183,290
Operating profit (loss)	22,640	22,810		40,280	42,390
Operating Segments [Member] | Aerospace [Member]
Segment Reporting Information [Line Items]
Net sales	42,240	39,100		80,570	76,890
Operating profit (loss)	7,010	6,450		12,750	11,040
Operating Segments [Member] | Specialty Products [Member]
Segment Reporting Information [Line Items]
Net sales	93,140	90,720		187,260	181,830
Operating profit (loss)	10,170	10,100		21,030	20,240
Corporate, Non-Segment [Member] | Corporate, Non-Segment [Member]
Segment Reporting Information [Line Items]
Operating profit (loss)	$ (8,710)	(7,840)		$ (17,100)	$ (6,940)	[1]
Selling, General and Administrative Expenses [Member]
Segment Reporting Information, Additional Information [Abstract]
Loss Contingency Accrual, Period Increase (Decrease)		$ (8,200)	$ (8,200)

[1] During the first quarter of 2018, the Company removed an obligation from its balance sheet, resulting in an approximate $8.2 million non-cash reduction in selling, general and administrative expenses. See Note 12, "Commitments and Contingencies," for further details.