Goodwill (Details) (USD $)	3 Months Ended
Mar. 31, 2012	Mar. 31, 2011
Goodwill and Intangible Assets Disclosure [Abstract]
Impairment loss for goodwill	$ 0	$ 0

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