Schedule II - Valuation and Qualifying Accounts (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012		Dec. 31, 2011		Dec. 31, 2010
Allowance for Doubtful Accounts [Member]
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Period	$ 215		$ 275		$ 302
Charged to Costs and Expenses	32		73		1
Deductions	0	[1]	(133)	[1]	(28)	[1]
Balance at End of Period	247		215		275
Allowance for Ship and Debit Credits [Member]
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Period	19,464		24,481		16,967
Charged to Costs and Expenses	154,803		142,742		130,993
Deductions	(151,227)	[2]	(147,759)	[2]	(123,479)	[2]
Balance at End of Period	$ 23,040		$ 19,464		$ 24,481

[1] Deductions relate to amounts written off against the allowances for doubtful accounts.

[2] Deductions relate to ship and debit credits issued which adjust the sell-in price from the standard distribution price to the pre-approved lower price. Refer to Note 2, Summary of Significant Accounting Policies, for the Company's revenue recognition policy, including the Company's accounting for ship and debit claims.