Note 2 - Revenue Recognition (Details Textual) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Accrued Oil and Gas Revenue	$ 12,228	$ 14,464

Represents the amount of accrued oil and gas revenue.

No definition available.

Name:	gdp_AccruedOilAndGasRevenue
Namespace Prefix:	gdp_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant