Text Block Comparison: Schedule of Amortization Expense Per Unit of Production [Table Text Block] (us-gaap:ScheduleOfAmortizationExpensePerUnitOfProductionTextBlock)

Documentation: Tabular disclosure of amortization expense per unit of production for oil and gas enterprises that follow the full cost method of accounting for investments in oil and gas properties.

(For last 10-K submitted to SEC as of March 31, 2018)