Quarterly report pursuant to Section 13 or 15(d)

Business and Summary of Significant Accounting Principles Business and Summary of Significant Accounting Principles (Revenue Recognition) (Details)

v3.4.0.3
Business and Summary of Significant Accounting Principles Business and Summary of Significant Accounting Principles (Revenue Recognition) (Details) - USD ($)
$ in Thousands
3 Months Ended
Mar. 31, 2016
Mar. 31, 2015
Dec. 31, 2015
Public Utilities, General Disclosures [Line Items]      
Revenues $ 231,098 $ 231,089  
Receivables 223,898   $ 208,384
High Cost Support Program [Member]      
Public Utilities, General Disclosures [Line Items]      
Revenues 16,200 $ 17,300  
Receivables $ 45,300