Annual report pursuant to Section 13 and 15(d)

Fair Value Measurements (Fair Value Of Assets And Liabilities) (Details)

v3.6.0.2
Fair Value Measurements (Fair Value Of Assets And Liabilities) (Details) - Credit Agreement 1.25B [Member] - USD ($)
Dec. 31, 2016
Dec. 31, 2015
Jan. 27, 2015
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]      
Secured debt     $ 1,250,000,000.00
Long-term Debt [Member]      
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]      
Secured debt $ 475,000,000 $ 500,000,000 $ 500,000,000
Secured debt, fair value 475,000,000 500,000,000  
Long-term Debt [Member] | Level 1 [Member]      
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]      
Secured debt, fair value 0 0  
Long-term Debt [Member] | Level 2 [Member]      
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]      
Secured debt, fair value 475,000,000 500,000,000  
Long-term Debt [Member] | Level 3 [Member]      
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]      
Secured debt, fair value 0 0  
Revolving Credit Facility [Member]      
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]      
Secured debt 40,000,000 140,000,000  
Secured debt, fair value 40,000,000 140,000,000  
Revolving Credit Facility [Member] | Level 1 [Member]      
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]      
Secured debt, fair value 0 0  
Revolving Credit Facility [Member] | Level 2 [Member]      
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]      
Secured debt, fair value 40,000,000 140,000,000  
Revolving Credit Facility [Member] | Level 3 [Member]      
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]      
Secured debt, fair value $ 0 $ 0