Segment Information (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Segment Reporting Information [Line Items]
Net sales	$ 213,370	$ 203,320	$ 413,200	$ 406,200
Operating profit (loss)	26,250	18,660	41,990	35,110
Packaging [Member]
Segment Reporting Information [Line Items]
Net sales	88,740	88,110	169,700	168,220
Operating profit (loss)	21,540	21,410	38,390	39,250
Aerospace [Member]
Segment Reporting Information [Line Items]
Net sales	47,580	44,090	93,000	84,590
Operating profit (loss)	6,930	3,550	11,930	7,010
Energy [Member]
Segment Reporting Information [Line Items]
Net sales	43,490	39,950	84,420	84,700
Operating profit (loss)	110	(3,090)	(3,790)	(6,700)
Engineered Components [Member]
Segment Reporting Information [Line Items]
Net sales	33,560	31,170	66,080	68,690
Operating profit (loss)	4,710	3,860	9,690	9,440
Corporate, Non-Segment [Member]
Segment Reporting Information [Line Items]
Operating profit (loss)	$ (7,040)	$ (7,070)	$ (14,230)	$ (13,890)