Annual report pursuant to Section 13 and 15(d)

Summary of Significant Accounting Policies - Supplemental Cash Flow Information (Details)

v3.6.0.2
Summary of Significant Accounting Policies - Supplemental Cash Flow Information (Details) - USD ($)
$ in Thousands
12 Months Ended
Dec. 31, 2016
Dec. 31, 2015
Dec. 31, 2014
Costs relating to construction included in accounts payable and accrued expenses $ 22,908 $ 28,665 $ 23,033
Interest paid, net of interest capitalized $ 50,270 49,542 $ 55,379
Dividend Declared [Member]      
Special Dividend   $ 21,200