Bankruptcy Proceedings and Emergence (Details) $ in Thousands	May 12, 2016 subsidiary	Jun. 30, 2018 USD ($)	Dec. 31, 2017 USD ($)
Reorganizations [Abstract]
Number of Subsidiaries Filing Chapter 11 Bankruptcy \| subsidiary	8
Bankruptcy Claims, amount reserved for outstanding claims \| $		$ 3,940	$ 3,933

Bankruptcy Claims, amount reserved for outstanding claims

No definition available.

Name:	pva_BankruptcyClaimsamountreservedforoutstandingclaims
Namespace Prefix:	pva_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant