Quarterly report pursuant to Section 13 or 15(d)

Basis of Presentation and Accounting Policies Deferred Gains (Details)

v3.5.0.2
Basis of Presentation and Accounting Policies Deferred Gains (Details) - USD ($)
$ in Thousands
9 Months Ended
Sep. 30, 2016
Sep. 30, 2015
Dec. 31, 2015
Dec. 31, 2014
Deferred Gains $ 122,841 $ 141,881 $ 135,909 $ 159,911
Increase (Decrease) in Deferred Charges 9,003 5,971    
Amortization of Deferred Gains 2,850 1,667    
Operating Expense [Member]        
Amortization of Deferred Gains 17,369 16,897    
Gain (Loss) on Asset Dispositions and Impairments, Net [Member]        
Amortization of Deferred Gains $ 1,852 $ 5,437