Goodwill and Other Intangible Assets Goodwill Rollforward (Details) $ in Thousands	6 Months Ended
	Jun. 30, 2018 USD ($)
Goodwill [Roll Forward]
Balance, beginning	$ 319,390
Translation and purchase accounting adjustments	(1,690)
Balance, ending	317,700
Packaging [Member]
Goodwill [Roll Forward]
Balance, beginning	166,400
Translation and purchase accounting adjustments	(1,690)
Balance, ending	164,710
Aerospace [Member]
Goodwill [Roll Forward]
Balance, beginning	146,430
Translation and purchase accounting adjustments	0
Balance, ending	146,430
Specialty Products [Member]
Goodwill [Roll Forward]
Balance, beginning	6,560
Translation and purchase accounting adjustments	0
Balance, ending	$ 6,560