Merger Agreement with Prysmian S.p.A. (Details)		3 Months Ended	4 Months Ended
	Dec. 03, 2017 USD ($) extension $ / shares	Mar. 30, 2018 USD ($)	Mar. 30, 2018 USD ($)	Feb. 16, 2018	Dec. 31, 2017 USD ($)	Sep. 25, 2012
Subordinated Convertible Notes Due 2029
Business Acquisition [Line Items]
Conversion price					$ 1,081.58
North America | 5.75% Senior Notes due 2022
Business Acquisition [Line Items]
Interest rate		5.75%	5.75%		5.75%	5.75%
Merger Agreement with Prysmian S.p.A.
Business Acquisition [Line Items]
Business acquisition, share price (in dollars per share) | $ / shares	$ 30.00
Percent of affirmative vote of total vote cast				75.34%
Percent of votes of total vote cast				99.00%
Number of extensions | extension	1
Extension period	90 days
Contract termination fee	$ 47,000,000
Payments for merger related costs			$ 18,600,000
Merger, stock cancellation, cash received in excess of | $ / shares	$ 30.00
Merger Agreement with Prysmian S.p.A. | Selling, General and Administrative Expenses
Business Acquisition [Line Items]
Payments for merger related costs		$ 2,400,000