Goodwill and Other Intangible Assets - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended
Jun. 30, 2013	Dec. 31, 2012
Goodwill And Intangible Assets Disclosure [Abstract]
Goodwill	$ 90.0	$ 97.0
Impairment charges in the second quarter	$ 6.8

Amount of loss from the write-down of an asset representing the future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

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