Annual report pursuant to Section 13 and 15(d)

Consolidated Statements of Cash Flows Supplemental Disclosures (Net Cash Paid or Received) (Details)

v3.6.0.2
Consolidated Statements of Cash Flows Supplemental Disclosures (Net Cash Paid or Received) (Details) - USD ($)
$ in Thousands
12 Months Ended
Dec. 31, 2016
Dec. 31, 2015
Dec. 31, 2014
Supplemental Cash Flow Elements [Abstract]      
Interest paid, net of amounts capitalized $ 84,546 $ 76,796 $ 74,618