Annual report pursuant to Section 13 and 15(d)

Share-Based Compensation (Schedule of Share-based Compensation Expense) (Details)

v3.8.0.1
Share-Based Compensation (Schedule of Share-based Compensation Expense) (Details) - USD ($)
$ in Thousands
12 Months Ended
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Share-based compensation expense - Equity-based $ 10,538 $ 4,813 $ 4,063
Share-based compensation expense - Liability-based 4,294 12,285 11,437
Settled share-based awards 6,351 0 0
Share-based compensation - capitalized oil and gas properties 3,287 7,376 6,201
General and Administrative Expense      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Share-based compensation 5,194 9,722 9,299
RSU equity awards      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Share-based compensation expense - Equity-based 10,225 4,536 3,797
Share-based compensation expense - Liability-based 0 0 0
Cash-settleable RSU awards      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Share-based compensation expense - Equity-based 0 0 0
Share-based compensation expense - Liability-based 4,294 12,285 11,437
401(k) CPE stock fund contributions      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Share-based compensation expense - Equity-based 313 277 266
Share-based compensation expense - Liability-based $ 0 $ 0 $ 0