Fair Value Measurements (Tables)

12 Months Ended

Dec. 31, 2012

Fair Value Measurements

Financial Assets and Liabilities Measured at Fair Value on a Recurring Basis

	Fair Value Measurements as of December 31, 2012
	Total		Level 1		Level 2		Level 3
	(in thousands)
Cash equivalents:
Money market securities	$	304,159	$	304,159	$	—	$	—
Fuel derivative contracts:
Crude oil call options		13,094		—		13,094		—
Total assets measured at fair value	$	317,253	$	304,159	$	13,094	$	—
Fuel derivative contracts:
Crude oil put options	$	397	$	—	$	397	$	—
Total liabilities measured at fair value	$	397	$	—	$	397	$	—

	Fair Value Measurements as of December 31, 2011
	Total		Level 1		Level 2		Level 3
	(in thousands)
Cash equivalents:
Money market securities	$	208,594	$	208,594	$	—	$	—
Fuel derivative contracts:
Crude oil call options		1,511		—		1,511		—
Crude oil collars		231		—		231		—
Heating oil call options		170		—		170		—
Heating oil collars		628		—		628		—
Total assets measured at fair value	$	211,134	$	208,594	$	2,540	$	—
Fuel derivative contracts:
Crude oil collars	$	90	$	—	$	90	$	—
Heating oil collars		427		—		427		—
Total liabilities measured at fair value	$	517	$	—	$	517	$	—

Schedule of reconciliation of assets measured at fair value on a recurring basis using unobservable inputs (Level 3)

	Auction rate securities (Level 3)*
	(in thousands)
Balance as of December 31, 2009	$	29,921
Sale of long-term investments		(26,672	)
Redemption		(4,075	)
Accretion of discount		844
Realized net gains (losses):
Included in earnings		1,168
Reclassified from other comprehensive income		(1,186	)
Balance as of December 31, 2010	$	—

*

As of December 31, 2012, 2011 and 2010, there were no assets measured at fair value on a nonrecurring basis using unobservable inputs (Level 3).