Fair Value of Assets and Liabilities (Tables)

3 Months Ended

Mar. 31, 2013

Fair Value of Assets and Liabilities

Schedule of certain of the entity's assets carried at fair value, categorized by the level of inputs used in the valuation of each asset

			Fair Value at Reporting Date Using
			Quoted Prices in Active Markets for Identical Assets		Significant Other Observable Inputs		Significant Unobservable Inputs
Description	Total		(Level 1)		(Level 2)		(Level 3)
Investment securities (1)	$	24,359	$	24,359	$	—	$	—

(1) Our investment securities, consisting of our 2,540,000 shares of TA, which are included in our other assets, are reported at fair value which is based on quoted market prices (Level 1 inputs).  Our historical cost basis for these securities is $9,267.  The unrealized gain for these securities as of March 31, 2013, is included in cumulative other comprehensive income in our condensed consolidated balance sheets.

Schedule of fair value of additional financial instruments

	March 31, 2013					December 31, 2012
	Carrying			Fair		Carrying			Fair
	Amount			Value		Amount			Value
Senior Notes, due 2014 at 7.875%	300,000			324,739		300,000			333,360
Senior Notes, due 2015 at 5.125%	280,000			295,026		280,000			298,926
Senior Notes, due 2016 at 6.3%	275,000			310,385		275,000			306,078
Senior Notes, due 2017 at 5.625%	300,000			331,805		300,000			335,173
Senior Notes, due 2018 at 6.7%	350,000			412,098		350,000			417,293
Senior Notes, due 2022 at 5%	500,000			529,555		500,000			531,343
Convertible Senior Notes, due 2027 at 3.8%	8,478			9,033		8,478			9,092
Unamortized discounts	(10,628		)	—		(11,120		)	—
Total financial liabilities	$	2,002,850		$	2,212,641	$	2,002,358		$	2,231,265