Segment Information (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018		Dec. 31, 2017		Dec. 31, 2016
Segment Reporting Information [Line Items]
Net sales	$ 211,350	$ 223,780	$ 224,910	$ 217,100	$ 195,210	$ 209,330	$ 213,370	$ 199,830	$ 877,140		$ 817,740		$ 794,020
Operating Profit (Loss)									122,070		89,170		(41,930)
Capital Expenditures									25,050		36,800		31,330
Depreciation and Amortization									44,020		46,870		44,860
Assets	1,100,520				1,033,200				1,100,520		1,033,200		1,051,650
Packaging [Member]
Segment Reporting Information [Line Items]
Net sales									368,200		344,570		341,340
Operating Profit (Loss)									84,590		80,610		78,630
Capital Expenditures									13,590		17,140		19,880
Depreciation and Amortization									21,620		21,630		22,120
Assets	435,140				431,680				435,140		431,680		423,460
Aerospace [Member]
Segment Reporting Information [Line Items]
Net sales									185,920		184,310		174,920
Operating Profit (Loss)									27,290		26,410		(90,540)
Capital Expenditures									1,190		3,370		3,950
Depreciation and Amortization									15,190		14,530		14,090
Assets	392,140				401,060				392,140		401,060		409,040
Specialty Products [Member]
Segment Reporting Information [Line Items]
Net sales									323,020		288,860		277,760
Operating Profit (Loss)									34,260		12,280		2,900
Capital Expenditures									5,380		6,830		7,470
Depreciation and Amortization									6,930		10,530		8,370
Assets	181,700				172,840				181,700		172,840		179,160
Corporate [Member]
Segment Reporting Information [Line Items]
Operating Profit (Loss)									(24,070)		(30,130)		(32,920)
Capital Expenditures									4,890	[1]	9,460	[1]	30
Depreciation and Amortization									280		180		280
Assets	$ 91,540				$ 27,620				$ 91,540		$ 27,620		$ 39,990

[1] (a) Corporate capital expenditures for the years ended December 31, 2018 and 2017, respectively, are primarily related to purchases of machinery and equipment formerly held under operating leases. These purchased assets were subsequently transferred from Corporate to the reportable segment utilizing the assets.