Debt Debt (Details) (USD $)	Dec. 31, 2012
Line of Credit Facility [Line Items]
Debt Instrument, Unused Borrowing Capacity, Amount	$ 64,586,000
Line of Credit Facility, Amount Outstanding	0
letters of credit outstanding under credit facility	17,322,000
Line of Credit Facility, Remaining Borrowing Capacity	47,263,000
Inventory Pledged as Collateral Under Line of Credit Facility	163,215,000
Letters of Credit Outstanding Under Letter of Credit Facilities	8,345,000
Number of Secured Letters of Credit Outstanding under Credit Facility	3
Restricted Cash for Secured Letter of Credit Agreements	8,527,000
Low Range Uncommitted Letter of Credit [Member]
Line of Credit Facility [Line Items]
Maximum Available Amounts under Letter of Credit Facilities	5,000,000
High Range Uncommittted Letter of Credit [Member]
Line of Credit Facility [Line Items]
Maximum Available Amounts under Letter of Credit Facilities	8,000,000
Uncommitted Letter of Credit [Member]
Line of Credit Facility [Line Items]
Maximum Available Amounts under Letter of Credit Facilities	$ 5,000,000