Business Acquisitions and Investments, General Cable Corporation Acquisitions (Details) - USD ($) $ in Thousands		1 Months Ended	12 Months Ended
		May 31, 2016	Dec. 31, 2015	Dec. 31, 2016	Dec. 31, 2014
Assets acquired and liabilities assumed [Abstract]
Goodwill			$ 54,881	$ 67,231	$ 54,975
General Cable Corporation [Member]
Business Acquisition [Line Items]
Percentage of equity interest acquired		100.00%
Revenue reported by acquired entity for last annual period			$ 96,000
Allocation of purchase price to the assets acquired and liabilities assumed [Abstract]
Purchase price		$ 67,451
Assets acquired and liabilities assumed [Abstract]
Receivables		3,130
Inventory		12,567
Other current and noncurrent assets	[1]	334
Property, plant and equipment, net		2,660
Intangible assets		42,440
Goodwill		12,746
Current liabilities		(6,426)
Net assets acquired		67,451
Cash acquired		200
Intangible assets acquired in business acquisition		42,400
General Cable Corporation [Member] | Customer Relationships [Member]
Assets acquired and liabilities assumed [Abstract]
Intangible assets acquired in business acquisition		$ 39,400
Estimated useful life of intangible assets		15 years
General Cable Corporation [Member] | Non-Compete Agreements [Member]
Assets acquired and liabilities assumed [Abstract]
Intangible assets acquired in business acquisition		$ 2,200
Estimated useful life of intangible assets		5 years
General Cable Corporation [Member] | Supply Agreement [Member]
Assets acquired and liabilities assumed [Abstract]
Intangible assets acquired in business acquisition		$ 800
Estimated useful life of intangible assets		1 year

[1] Other current and noncurrent assets includes $0.2 million of cash acquired.