Inventories (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014
Inventory Disclosure [Abstract]
Raw materials and work in process	$ 36,982	$ 37,175
Supplies and service parts	42,818us-gaap_OtherInventoryNetOfReserves	33,760us-gaap_OtherInventoryNetOfReserves
Finished products	28,692	26,992
Inventory at FIFO cost	108,492us-gaap_FIFOInventoryAmount	97,927us-gaap_FIFOInventoryAmount
Excess of FIFO cost over LIFO cost	(13,463)	(13,100)
Total inventory, net	$ 95,029us-gaap_InventoryNet	$ 84,827us-gaap_InventoryNet

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

The amount of FIFO (first in first out) inventory present at the reporting date when inventory is also valued using different valuation methods.

+ References

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-Publisher FASB

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- Definition

Carrying amount, net of valuation reserves and adjustments, as of the balance sheet date of merchandise or goods held by the company that are readily available for sale.

+ References

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

-Publisher FASB

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-Name Staff Accounting Bulletin (SAB)

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- Definition

Amount after valuation and LIFO reserves of inventory expected to be sold, or consumed within one year or operating cycle, if longer.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

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- Definition

The aggregate carrying amount, net of valuation reserves and adjustments, as of the balance sheet date of items which are partially completed at the time of measurement and unprocessed items that will go through the production process and become part of the final product. This element may be used when the reporting entity combines work in process and raw materials into an aggregate amount.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

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-Subparagraph (SAB TOPIC 5.BB)

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- Definition

Carrying amount, net of valuation reserves and allowances, as of the balance sheet date of inventories not otherwise specified in the taxonomy.

+ References

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-Publisher FASB

-Name Accounting Standards Codification

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-Subparagraph (SX 210.5-02.6)

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