Inventories and natural gas in storage

9 Months Ended

Sep. 30, 2015

Natural gas in storage for the Company's regulated operations is generally carried at average cost, or cost using the last-in, first-out method. Crude oil and refined products at Dakota Prairie Refinery are carried at lower of cost or market value using the last-in, first-out method. All other inventories are stated at the lower of average cost or market value. The portion of the cost of natural gas in storage expected to be used within one year is included in inventories. Inventories consisted of:



	September 30, 2015		September 30, 2014		December 31, 2014
	(In thousands)
Aggregates held for resale	$	115,736	$	106,623	$	108,161
Asphalt oil	33,581		33,551		42,135
Natural gas in storage (current)	28,222		29,979		19,302
Materials and supplies	19,404		58,011		54,282
Merchandise for resale	15,563		24,566		24,420
Crude oil	6,465		—		5,045
Refined products	5,889		—		—
Other	33,481		36,471		36,065
Total	$	258,341	$	289,201	$	289,410

The remainder of natural gas in storage, which largely represents the cost of gas required to maintain pressure levels for normal operating purposes, is included in other assets and was $49.3 million, $47.4 million and $49.3 million at September 30, 2015 and 2014, and December 31, 2014, respectively.