Annual report pursuant to Section 13 and 15(d)

Supplemental Information On Oil And Gas Producing Activities (Standardized Measure Of Discounted Future Net Cash Flows Relating To Proved Oil Reserves) (Detail)

v3.3.1.900
Supplemental Information On Oil And Gas Producing Activities (Standardized Measure Of Discounted Future Net Cash Flows Relating To Proved Oil Reserves) (Detail) - USD ($)
$ in Thousands
Dec. 31, 2015
Dec. 31, 2014
Dec. 31, 2013
Dec. 31, 2012
Standardized Measure of Discounted Future Net Cash Flows Relating to Proved Oil Reserves        
Future cash inflows $ 143,276 $ 823,657 $ 733,761  
Future production costs (83,617) (308,806) (226,681)  
Future development costs [1] (11,159) (136,137) (164,142)  
Future income tax expense (21,598) (178,283) (155,344)  
Future net cash flows 26,902 200,431 187,594  
Discount to present value at 10% annual rate 239 (51,044) (50,158)  
Standardized measure of discounted future net cash flows 27,141 149,387 137,436 $ 152,902
International [Member]        
Standardized Measure of Discounted Future Net Cash Flows Relating to Proved Oil Reserves        
Future cash inflows 140,190 814,059 725,485  
Future production costs (81,973) (307,331) (223,643)  
Future development costs [1] (10,900) (136,137) (164,142)  
Future income tax expense (21,598) (177,924) (154,519)  
Future net cash flows 25,719 192,667 183,181  
Discount to present value at 10% annual rate 491 (47,528) (48,859)  
Standardized measure of discounted future net cash flows 26,210 145,139 134,322  
United States [Member]        
Standardized Measure of Discounted Future Net Cash Flows Relating to Proved Oil Reserves        
Future cash inflows 3,086 9,598 8,276  
Future production costs (1,644) (1,475) (3,038)  
Future development costs [1] (259)      
Future income tax expense   (359) (825)  
Future net cash flows 1,183 7,764 4,413  
Discount to present value at 10% annual rate (252) (3,516) (1,299)  
Standardized measure of discounted future net cash flows $ 931 $ 4,248 $ 3,114  
[1] Includes costs expected to be incurred to abandon the properties.