Quarterly report pursuant to Section 13 or 15(d)

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

v3.5.0.2
Business and Summary of Significant Accounting Principles (Revenue Recognition) (Details) - USD ($)
$ in Thousands
3 Months Ended 9 Months Ended
Sep. 30, 2016
Sep. 30, 2015
Sep. 30, 2016
Sep. 30, 2015
Dec. 31, 2015
Public Utilities, General Disclosures [Line Items]          
Revenues $ 236,655 $ 258,573 $ 701,519 $ 737,190  
Document Period End Date     Sep. 30, 2016    
Receivables 200,294   $ 200,294   $ 208,384
High Cost Support Program [Member]          
Public Utilities, General Disclosures [Line Items]          
High cost support payment percent     60.00%    
Revenues 15,900 $ 16,500 $ 48,400 $ 50,600  
Receivables $ 44,700   $ 44,700