Inventory (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Inventory [Line Items]
Percentage of LIFO Inventory	92.00%us-gaap_PercentageOfLIFOInventory	92.00%us-gaap_PercentageOfLIFOInventory
Excess of Replacement or Current Costs over Stated LIFO Value	$ 139,468	$ 149,507
Inventory Valuation Reserves	4,417us-gaap_InventoryValuationReserves	3,747us-gaap_InventoryValuationReserves
Inventory Valuation Reserve
Inventory [Line Items]
Reserves for Obsolete Inventories, Period Increase (Decrease)	$ 670	$ 247	$ (300)

The excess of replacement or current cost over the stated LIFO (last in first out) inventory value when the LIFO inventory method is utilized.

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- Definition

Amount of valuation reserve for inventory.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.6(a))

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-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 6

-Subparagraph a

-Article 5

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 330

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Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 235

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-Section S99

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-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e24092-122690

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 330

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-Section S99

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-Name Regulation S-X (SX)

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+ Details

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- Definition

The percentage of LIFO (last in first out) inventory to total inventory as of the balance sheet date if other than 100 percent.

+ References

No definition available.

+ Details

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- Definition

Total increases or decreases in allowances and reserves, the valuation and qualifying accounts that are either netted against the cost of an asset (in order to value it at its carrying value) or that reflect a liability established to represent expected future costs.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 235

-SubTopic 10

-Section S99

-Paragraph 4

-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e24092-122690

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