Segment Information Segment Information (Details) - USD ($) $ in Thousands	3 Months Ended			9 Months Ended
	Sep. 30, 2018	Mar. 31, 2018	Sep. 30, 2017	Sep. 30, 2018		Sep. 30, 2017
Segment Reporting Information [Line Items]
Net sales	$ 223,780		$ 209,330	$ 665,790		$ 622,530
Operating profit (loss)	29,880		28,290	96,610		70,620
Operating Segments [Member] | Packaging [Member]
Segment Reporting Information [Line Items]
Net sales	95,250		89,560	278,540		259,260
Operating profit (loss)	22,060		23,140	64,450		61,630
Operating Segments [Member] | Aerospace [Member]
Segment Reporting Information [Line Items]
Net sales	49,070		48,550	140,500		141,550
Operating profit (loss)	8,290		7,810	20,680		19,860
Operating Segments [Member] | Specialty Products [Member]
Segment Reporting Information [Line Items]
Net sales	79,460		71,220	246,750		221,720
Operating profit (loss)	7,720		5,000	26,610		11,770
Corporate, Non-Segment [Member] | Corporate, Non-Segment [Member]
Segment Reporting Information [Line Items]
Operating profit (loss)	$ (8,190)		$ (7,660)	$ (15,130)	[1]	$ (22,640)
Selling, General and Administrative Expenses [Member]
Segment Reporting Information, Additional Information [Abstract]
Loss Contingency Accrual, Period Increase (Decrease)		$ (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 10, "Commitments and Contingencies," for further details.