XML 101 R78.htm IDEA: XBRL DOCUMENT v3.8.0.1
Supplementary Information For Oil And Gas Producing Activities (Summary Of Capitalized Costs Of Unproved Properties Excluded From Amortization) (Details) - USD ($)
$ in Thousands
12 Months Ended
Sep. 30, 2017
Sep. 30, 2016
Sep. 30, 2015
Sep. 30, 2014
Capitalized Costs of Unproved Properties Excluded from Amortization [Line Items]        
Acquisition Costs $ 0 $ 0 $ 0  
Development Costs 4,388 6,707 416  
Exploration Costs 2,376 7,593 3,419  
Capitalized Interest 235 149 88  
Capitalized Costs of Unproved Properties Excluded from Amortization, Total 6,999 $ 14,449 $ 3,923  
Capitalized Costs Of Unproved Properties Cumulative Balance [Member]        
Capitalized Costs of Unproved Properties Excluded from Amortization [Line Items]        
Acquisition Costs 55,193      
Development Costs 11,879      
Exploration Costs 13,388      
Capitalized Interest 472      
Capitalized Costs of Unproved Properties Excluded from Amortization, Total $ 80,932      
Costs Incurred Prior To Fiscal 2015 [Member]        
Capitalized Costs of Unproved Properties Excluded from Amortization [Line Items]        
Acquisition Costs       $ 55,193
Development Costs       368
Exploration Costs       0
Capitalized Interest       0
Capitalized Costs of Unproved Properties Excluded from Amortization, Total       $ 55,561