Annual report pursuant to Section 13 and 15(d)

Long-Term Debt (Schedule Of Long-Term Debt) (Details)

v3.6.0.2
Long-Term Debt (Schedule Of Long-Term Debt) (Details) - USD ($)
Dec. 31, 2016
Dec. 31, 2015
Jan. 27, 2015
Debt Instrument [Line Items]      
Long-term Debt, Gross $ 515,000,000 $ 640,000,000  
Total long-term debt 509,878,000 633,108,000  
Less: current maturities (25,000,000) (25,000,000)  
Long-term debt, net of current maturities 484,878,000 608,108,000  
Credit Agreement 1.25B [Member]      
Debt Instrument [Line Items]      
Secured debt     $ 1,250,000,000.00
Debt Issuance Costs, Net (5,122,000) (6,892,000) (1,900,000)
Credit Agreement Terminated January 27, 2015 [Member]      
Debt Instrument [Line Items]      
Debt Issuance Costs, Net     (2,400,000)
Long-term Debt [Member] | Credit Agreement 1.25B [Member]      
Debt Instrument [Line Items]      
Secured debt 475,000,000 500,000,000 500,000,000
Long-term Debt [Member] | Credit Agreement Terminated January 27, 2015 [Member]      
Debt Instrument [Line Items]      
Secured debt     $ 228,100,000
Revolving Credit Facility [Member] | Credit Agreement 1.25B [Member]      
Debt Instrument [Line Items]      
Secured debt $ 40,000,000 $ 140,000,000