XML 96 R64.htm IDEA: XBRL DOCUMENT v3.19.3.a.u2
Basis of Presentation and Significant Accounting Policies - Concentrations of Credit Risk (Details) - USD ($)
$ in Thousands
12 Months Ended
Dec. 31, 2019
Dec. 31, 2018
Dec. 31, 2017
Concentration Risk      
Bad debt expense $ 2,567 $ 1,677 $ 5,144
Trade Receivables | Customer Concentration Risk | Anadarko      
Concentration Risk      
Concentration risk (percent)   13.00%  
Trade Receivables | Customer Concentration Risk | Williams Partners      
Concentration Risk      
Concentration risk (percent)   11.00%