Goodwill and Other Intangibles (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Finite-Lived Intangible Assets [Line Items]
Goodwill acquired during the period		$ 84,795	$ 53,604
Goodwill impairment charges		(24,254)	0	$ 0
Amortization expense		18,900	4,000	$ 3,200
SL Industries, Inc. (SLI) and EME
Finite-Lived Intangible Assets [Line Items]
Intangibles	$ 120,700	120,700
Electrical products
Finite-Lived Intangible Assets [Line Items]
Goodwill acquired during the period		84,795
Performance materials
Finite-Lived Intangible Assets [Line Items]
Goodwill acquired during the period		0	$ 32,336
Goodwill impairment charges	$ (24,254)	$ (24,300)