Supplemental Cash Flow Information

6 Months Ended

Jun. 30, 2013

Supplemental Cash Flow Elements [Abstract]

Supplemental Cash Flow Information

10. Supplemental Cash Flow Information

The following table provides information regarding the net changes in components of operating assets and liabilities.

	Six Months Ended June 30,
	2013			2012
(Increase) decrease in:
Accounts receivable	$	(82,346	)	$	6,698
Inventories	(858		)	28,146
Other current assets	11,135			5,197
Increase (decrease) in:
Accounts payable	66,860			(9,549		)
Accrued liabilities	3,741			(10,568		)
Net changes in components of operating assets and liabilities	$	(1,468	)	$	19,924

Payments of interest and commitment fees were $18.9 million and $21.6 million for the six months ended June 30, 2013 and June 30, 2012, respectively.

At June 30, 2013 and June 30, 2012, we had incurred liabilities for fixed and intangible asset additions totaling $20.8 million and $8.1 million, respectively, that had not been paid at the end of the second quarter, and, therefore, were not included in the caption “Payments to acquire fixed and intangible assets” under Cash Flows from Investing Activities in the Unaudited Condensed Consolidated Statements of Cash Flows.

At June 30, 2013, we had incurred liabilities for other asset additions totaling $0.2 million that had not been paid at the end of the second quarter, and, therefore, were not included in the caption "Other, net" under Cash Flows from Investing Activities in the Unaudited Condensed Consolidated Statements of Cash Flows.