Fair Value Measurements (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2013 Recurring basis Total estimated fair value	Dec. 31, 2012 Recurring basis Total estimated fair value	Mar. 31, 2013 Recurring basis Total estimated fair value Forward fixed price purchase and sale contracts	Dec. 31, 2012 Recurring basis Total estimated fair value Forward fixed price purchase and sale contracts	Mar. 31, 2013 Recurring basis Total estimated fair value Swap agreements and option contracts	Dec. 31, 2012 Recurring basis Total estimated fair value Swap agreements and option contracts	Mar. 31, 2013 Recurring basis Total estimated fair value Interest rate cap	Dec. 31, 2012 Recurring basis Total estimated fair value Interest rate cap	Mar. 31, 2013 Recurring basis Total estimated fair value Interest rate collar and swap	Dec. 31, 2012 Recurring basis Total estimated fair value Interest rate collar and swap	Mar. 31, 2013 Recurring basis Total estimated fair value Foreign currency derivatives	Dec. 31, 2012 Recurring basis Total estimated fair value Foreign currency derivatives	Mar. 31, 2013 Recurring basis Total estimated fair value Inventories	Dec. 31, 2012 Recurring basis Total estimated fair value Inventories	Mar. 31, 2013 Recurring basis Level 1	Dec. 31, 2012 Recurring basis Level 1	Mar. 31, 2013 Recurring basis Level 1 Swap agreements and option contracts	Dec. 31, 2012 Recurring basis Level 1 Swap agreements and option contracts	Mar. 31, 2013 Recurring basis Level 2	Dec. 31, 2012 Recurring basis Level 2	Mar. 31, 2013 Recurring basis Level 2 Forward fixed price purchase and sale contracts	Dec. 31, 2012 Recurring basis Level 2 Forward fixed price purchase and sale contracts	Mar. 31, 2013 Recurring basis Level 2 Swap agreements and option contracts	Dec. 31, 2012 Recurring basis Level 2 Swap agreements and option contracts	Mar. 31, 2013 Recurring basis Level 2 Interest rate cap	Dec. 31, 2012 Recurring basis Level 2 Interest rate cap	Mar. 31, 2013 Recurring basis Level 2 Interest rate collar and swap	Dec. 31, 2012 Recurring basis Level 2 Interest rate collar and swap	Mar. 31, 2013 Recurring basis Level 2 Foreign currency derivatives	Dec. 31, 2012 Recurring basis Level 2 Foreign currency derivatives	Mar. 31, 2013 Recurring basis Level 2 Inventories	Dec. 31, 2012 Recurring basis Level 2 Inventories	Mar. 31, 2013 Recurring basis Level 3	Mar. 31, 2013 Recurring basis Level 3 Forward fixed price purchase and sale contracts
Assets:
Hedged inventories														$ 336,558	$ 526,107																	$ 336,558	$ 526,107
Derivative assets				18,339	48,062	353	179	30	35				145					21	54			13,685	48,062	332	125	30	35				145				4,654
Broker margin deposits		28,429	54,726													28,429	54,726
Pension plan		17,795	17,158													17,795	17,158
Total assets		401,504	646,412													46,245	71,938			350,605	574,474													4,654
Liabilities:
Derivative liabilities				(4,080)	(34,474)	(24)	(54)			(11,924)	(13,402)	(175)						(21)	(54)			(4,080)	(34,474)	(3)				(11,924)	(13,402)	(175)
Total liabilities		(16,203)	(47,930)													(21)	(54)			(16,182)	(47,876)
Changes in fair value of Level 3 financial assets
Reclass of Level 2 inputs	15,127
Change in fair value recorded in Cost of Sales	(10,473)
Fair value at the end of the period	$ 4,654