Accounts Receivable Allowance for doubtful accounts (Details) (Allowance for Doubtful Accounts [Member], USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 28, 2011	Dec. 31, 2009
Allowance for Doubtful Accounts [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for Doubtful Accounts Receivable	$ 103		$ 346	$ 167	$ 327
Allowance for Doubtful Accounts Receivable, Additions Charged to Costs and Expenses	103	(58)	214
Allowance for Doubtful Accounts Receivable, Write-offs, Net of Recoveries	0	121	195
Allowance for doubtful accounts retained by parent	$ 167	$ 0	$ 0