Decommissioning Liabilities (Tables)

6 Months Ended

Jun. 30, 2015

Decommissioning Liabilities [Abstract]

Summary the activity for company's decommissioning liabilities

	Six Months Ended June 30,
	2015		2014
Decommissioning liabilities, December 31, 2014 and 2013, respectively	$	88,000	$	83,519
Liabilities acquired and incurred		1,176		797
Accretion		2,418		2,344
Revisions in estimated timing and cash flows		1,482		(1,040)
Total decommissioning liabilities, June 30, 2015 and 2014, respectively	$	93,076	$	85,620