Annual report pursuant to Section 13 and 15(d)

Acquisitions and Divestitures - Business Acquisition Pro Forma Information Incremental Items (Parenthetical) (Details)

v3.6.0.2
Acquisitions and Divestitures - Business Acquisition Pro Forma Information Incremental Items (Parenthetical) (Details) - USD ($)
$ in Thousands
12 Months Ended
Dec. 31, 2016
Dec. 31, 2015
Dec. 31, 2014
Business Acquisition [Line Items]      
Long-term debt, less current maturities $ 1,012,455 $ 1,196,855  
Federal statutory income tax rate 35.00% 35.00% 35.00%
Woodside Properties      
Business Acquisition [Line Items]      
Long-term debt, less current maturities     $ 55,000
Federal statutory income tax rate     35.00%
Woodside Properties | Revolving Credit Facility      
Business Acquisition [Line Items]      
Effective interest rate     1.80%