Accrued Liabilities (Tables)

3 Months Ended

Mar. 31, 2014

Accrued Liabilities

Schedule of accrued liabilities

	December 31, 2013		March 31, 2014
Salaries and wages	$	6,768	$	6,938
Accrued gas and equipment purchases	8,035		10,857
Accrued property and other taxes	5,448		4,095
Accrued professional fees	1,335		899
Accrued employee benefits	2,898		3,557
Accrued warranty liability	2,545		2,802
Accrued interest	4,216		981
Other	15,500		12,446
	$	46,745	$	42,575