Derivative Financial Instruments (Details Textuals)	12 Months Ended
Dec. 31, 2013
Commodity Derivatives Authorization [Abstract]
Commodity Derivatives Board Authorization	50.00%

Per the Company's heding policy, the percentage of forecast production that is hedged and requires Board authorization.

No definition available.

Name:	upl_CommodityDerivativesBoardAuthorization
Namespace Prefix:	upl_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration