Quarterly report pursuant to Section 13 or 15(d)

Basis of Presentation and Accounting Policies Deferred Gains (Details)

v3.7.0.1
Basis of Presentation and Accounting Policies Deferred Gains (Details) - USD ($)
$ in Thousands
6 Months Ended
Jun. 30, 2017
Jun. 30, 2016
Dec. 31, 2016
Dec. 31, 2015
Deferred Gains $ 29,447 $ 38,010 $ 33,910 $ 43,298
Amortization of Deferred Gains (364) (1,153)    
Operating Expense [Member]        
Amortization of Deferred Gains (4,099) (4,099)    
Gain (Loss) on Asset Dispositions and Impairments, Net [Member]        
Amortization of Deferred Gains $ 0 $ (36)