Accrued Liabilities and Deferred Credits (Tables)

6 Months Ended

Jun. 30, 2013

Payables and Accruals [Abstract]

Accrued Liabilities and Deferred Credits

Accrued liabilities and deferred credits consist of the following:

	June 30, 2013		December 31, 2012
Accrued compensation	$	2,442	$	3,529
Deferred revenue	30,286		27,962
Environmental and insurance liabilities	1,541		1,621
Other accrued liabilities	16,354		9,240
Total accrued liabilities and deferred credits	$	50,623	$	42,352