Fair Value Measurements

12 Months Ended

Dec. 31, 2012

Fair Value Disclosures [Abstract]

Fair Value Measurements

Fair Value Measurements

The Company reports certain assets and liabilities at fair value, which is defined as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date (exit price). The following tables summarize, by level within the fair value hierarchy, the Company's assets and liabilities at December 31 that were accounted for at fair value on a recurring basis:

	2012
	Level 1	Level 2		Total
Derivative instruments
Risk management assets - Commodity forward contracts	1,395	13,032		14,427
Risk management liabilities - Commodity forward contracts	—	(13,694	)	(13,694	)
Firm commitments
Hedged portion of firm commitment	—	399		399
Hedged portion of firm commitment	—	(13,032	)	(13,032	)
	2011
	Level 1	Level 2		Total
Derivative instruments
Risk management assets - Commodity forward contracts	1,090	1,347		2,437
Risk management liabilities - Commodity forward contracts	—	(4,235	)	(4,235	)
Firm commitments
Hedged portion of firm commitment	—	3,262		3,262
Marketable securities
Available-for-sale equity securities	30,113	—		30,113

The Level 2 measurements are derived using forward curves supplied by industry recognized and unrelated third-party services. There were no transfers in and out of Levels 1 and 2 of the fair value hierarchy in 2012 and 2011.

See Note 17 for the measurement of certain assets at fair value on a nonrecurring basis.

In addition to the assets and liabilities above, the Company has other financial assets and liabilities subject to fair value measures. These financial assets and liabilities include cash and cash equivalents, accounts receivable, net, accounts payable and long-term debt, all of which are recorded at carrying value. Further, the Company has current marketable securities that are carried at amortized cost. The amounts reported in the consolidated balance sheets for cash and cash equivalents, current marketable securities, accounts receivable, net and accounts payable approximate their fair value due to the short maturities of these instruments. The carrying and fair values of the Company's long-term debt at December 31 are summarized in the table below. The Company's long-term debt instruments are publicly-traded. A market approach, based upon quotes from financial reporting services, is used to measure the fair value of the Company's long-term debt. Because the Company's long-term debt instruments may not be actively traded, the inputs used to measure the fair value of the Company's long-term debt are classified as Level 2 inputs within the fair value hierarchy.

	2012				2011
	Carrying Value		Fair Value		Carrying Value		Fair Value
6 5/8% senior notes due 2016	$	—	$	—	$	249,674	$	254,890
3.60% senior notes due 2022	248,872		251,125		—		—
6 ½% senior notes due 2029	100,000		119,738		100,000		108,834
6 ¾% senior notes due 2032	250,000		283,168		250,000		263,988
6 ½% GO Zone Senior Notes Due 2035	89,000		102,095		89,000		93,090
6 ½% IKE Zone Senior Notes Due 2035	65,000		74,564		65,000		67,987
Loan related to tax-exempt waste disposal revenue bonds due 2027	10,889		10,889		10,889		10,889