Summary of Significant Accounting Policies Accounting Policies (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Accounting Policies [Abstract]
Outgoing freight expenses	$ 49,622	$ 48,497	$ 44,672
Goodwill	$ 6,680us-gaap_Goodwill	$ 6,680us-gaap_Goodwill

Cost incurred during the reporting period in transporting goods and services to customers. Includes freight-out costs.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 235

-SubTopic 10

-Section 50

-Paragraph 3

-URI http://asc.fasb.org/extlink&oid=6367646&loc=d3e18780-107790

Reference 2: http://www.xbrl.org/2003/role/presentationRef

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

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-Name Accounting Standards Codification

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

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Handling Costs

-URI http://asc.fasb.org/extlink&oid=6514758

Reference 5: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

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Reference 7: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Shipping Costs

-URI http://asc.fasb.org/extlink&oid=6525344

Name:	us-gaap_ShippingHandlingAndTransportationCosts
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration