Fair Value of Financial Instruments (Tables)

12 Months Ended

Dec. 31, 2012

Assets and Liabilities Measured At Fair Value on Recurring Basis

The Company’s assets and liabilities measured at fair value on a recurring basis at December 31, 2012 and 2011, were as follows:

	Fair Value Measurement at December 31, 2012 Using
	Total			Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)			Significant Unobservable Inputs (Level 3)
Interest rate swap derivative instruments – net liability position	$	(11,163	)	$	—	$	(11,163	)	$	—
Fuel hedge derivative instruments –net asset position	$	1,187		$	—	$	—		$	1,187
Restricted assets	$	33,425		$	33,425	$	—		$	—

	Fair Value Measurement at December 31, 2011 Using
	Total			Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)			Significant Unobservable Inputs (Level 3)
Interest rate swap derivative instruments – net liability position	$	(9,118	)	$	—	$	(9,118	)	$	—
Fuel hedge derivative instruments – net asset position	$	3,506		$	—	$	—		$	3,506
Restricted assets	$	30,728		$	30,728	$	—		$	—

Change in Fair Value for Level 3 Derivatives

The following table summarizes the change in the fair value for Level 3 derivatives for the years ended December 31, 2012 and 2011:

	Level 3 Derivatives
Balance as of December 31, 2010	$	4,730
Realized gains included in earnings		(4,297	)
Unrealized gains included in AOCL		3,073
Balance as of December 31, 2011		3,506
Realized gains included in earnings		(4,513	)
Unrealized gains included in AOCL		2,194
Balance as of December 31, 2012	$	1,187