Fair Value Measurements (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012
Assets:
Pension plan	$ 18,267	$ 17,158
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	(6,233)
Fair value at the end of the period	8,894
Recurring basis | Total estimated fair value
Assets:
Broker margin deposits	21,792	54,726
Pension plan	18,267	17,158
Total assets	538,510	646,412
Liabilities:
Total liabilities	(53,949)	(47,930)
Recurring basis | Total estimated fair value | Forward fixed price purchase and sale contracts
Assets:
Derivative assets	46,007	48,062
Liabilities:
Derivative liabilities	(38,197)	(34,474)
Recurring basis | Total estimated fair value | Mark to market loss related to RIN forward commitments
Liabilities:
Derivative liabilities	(6,166)
Recurring basis | Total estimated fair value | Swap agreements and option contracts
Assets:
Derivative assets	116	179
Liabilities:
Derivative liabilities	(108)	(54)
Recurring basis | Total estimated fair value | Interest rate cap
Assets:
Derivative assets	26	35
Recurring basis | Total estimated fair value | Interest rate collar and swap
Liabilities:
Derivative liabilities	(9,462)	(13,402)
Recurring basis | Total estimated fair value | Foreign currency derivatives
Assets:
Derivative assets		145
Liabilities:
Derivative liabilities	(16)
Recurring basis | Total estimated fair value | Inventories
Assets:
Hedged inventories	452,302	526,107
Recurring basis | Level 1
Assets:
Broker margin deposits	21,792	54,726
Pension plan	18,267	17,158
Total assets	40,133	71,938
Liabilities:
Total liabilities	(74)	(54)
Recurring basis | Level 1 | Swap agreements and option contracts
Assets:
Derivative assets	74	54
Liabilities:
Derivative liabilities	(74)	(54)
Recurring basis | Level 2
Assets:
Total assets	484,301	574,474
Liabilities:
Total liabilities	(48,692)	(47,876)
Recurring basis | Level 2 | Forward fixed price purchase and sale contracts
Assets:
Derivative assets	31,931	48,062
Liabilities:
Derivative liabilities	(33,014)	(34,474)
Recurring basis | Level 2 | Mark to market loss related to RIN forward commitments
Liabilities:
Derivative liabilities	(6,166)
Recurring basis | Level 2 | Swap agreements and option contracts
Assets:
Derivative assets	42	125
Liabilities:
Derivative liabilities	(34)
Recurring basis | Level 2 | Interest rate cap
Assets:
Derivative assets	26	35
Recurring basis | Level 2 | Interest rate collar and swap
Liabilities:
Derivative liabilities	(9,462)	(13,402)
Recurring basis | Level 2 | Foreign currency derivatives
Assets:
Derivative assets		145
Liabilities:
Derivative liabilities	(16)
Recurring basis | Level 2 | Inventories
Assets:
Hedged inventories	452,302	526,107
Recurring basis | Level 3
Assets:
Total assets	14,076
Liabilities:
Total liabilities	(5,183)
Recurring basis | Level 3 | Forward fixed price purchase and sale contracts
Assets:
Derivative assets	14,076
Liabilities:
Derivative liabilities	$ (5,183)