Net assets from acquisition (Tables)

3 Months Ended

Jun. 30, 2012

Business Combinations [Abstract]

Schedule of Business Acquisitions, by Acquisition [Table Text Block]

The following presents the preliminary values assigned to the net assets acquired as of the acquisition date:

	(in thousands)
Total acquisition cost	$	326,782
Recognized amounts of identifiable assets acquired and liabilities assumed:
Assets acquired:
Natural gas and crude oil properties - proved	$	126,101
Natural gas and crude oil properties - unproved	208,098
Other assets	23,589
Total assets acquired	357,788
Liabilities assumed:
Asset retirement obligation	13,870
Environmental liability	10,100
Other liabilities	7,036
Total liabilities assumed	31,006
Total identifiable net assets acquired	$	326,782