Debt (Schedule Of Letters Of Credit) (Details)	Dec. 31, 2016 USD ($)
Debt Instrument [Line Items]
Letters of credit, Limit	$ 207,400,000
Letters of credit, Used	55,500,000
Letters of credit, Available	151,900,000
Bi-lateral Facility [Member]
Debt Instrument [Line Items]
Letters of credit, Limit	25,000,000
Letters of credit, Used	19,200,000
Letters of credit, Available	5,800,000
Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Letter of credit maximum sublimit	150,000,000
Letters of credit, Limit	200,000,000
Letters of credit, Available	150,000,000
Accounts Receivable Securitization Facility [Member]
Debt Instrument [Line Items]
Letters of credit, Limit	32,200,000
Letters of credit, Used	36,200,000
Letters of credit, Available	(4,000,000)
Foreign Line Of Credit [Member]
Debt Instrument [Line Items]
Letters of credit, Limit	200,000
Letters of credit, Used	100,000
Letters of credit, Available	$ 100,000