XML 104 R80.htm IDEA: XBRL DOCUMENT v3.8.0.1
Equity Method Investments Narrative (Details) - USD ($)
$ in Thousands
Dec. 31, 2017
Dec. 31, 2016
Schedule of Equity Method Investments [Line Items]    
Equity method investments $ 106,465 $ 101,080
CP LLC    
Schedule of Equity Method Investments [Line Items]    
Equity method investment, ownership percentage 50.00%  
Rangeland Rio    
Schedule of Equity Method Investments [Line Items]    
Equity method investment, ownership percentage 33.00%