Immaterial Restatement of Goodwill - Summary of Goodwill Impairment Charges (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended	6 Months Ended	9 Months Ended	12 Months Ended
Sep. 30, 2012	Jul. 01, 2012	Jul. 01, 2012	Sep. 30, 2012	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Impairment of goodwill	$ (686)	$ 32,369	$ 47,294	$ 46,608	$ 51,157	$ 0	$ 0
Restatement Adjustment [Member]
Impairment of goodwill	(486)	5,780	5,780	5,294
Previously Reported
Impairment of goodwill	$ (200)	$ 26,589	$ 41,514	$ 41,314

Loss recognized during the period that results from the write-down of goodwill after comparing the implied fair value of reporting unit goodwill with the carrying amount of that goodwill. Goodwill is assessed at least annually for impairment.

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+ Details