Description of Business and Significant Accounting Policies (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Beginning balance	$ 1,015	$ 701	$ 566
Additions	782	601	139
Deductions	(41)	(287)	(4)
Ending balance	$ 1,756	$ 1,015	$ 701