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Acquisitions and Dispositions - Additional Information (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2014 Trust Investment	Mar. 31, 2013
Business Combinations [Abstract]
Number of limited partnerships	18
Number of business income trusts	2
Purchase of non-controlling interests	$ 48	$ 1

X

- Definition

Number of business income trusts.

+ References

No definition available.

+ Details

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X

- Definition

Number of limited partnerships.

+ References

No definition available.

+ Details

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Namespace Prefix:	pnrg_
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X

- Details

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X

- Definition

The cash outflow during the period for redemption of redeemable noncontrolling interests.

+ References

No definition available.

+ Details

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Data Type:	xbrli:monetaryItemType
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