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Asset Impairment Charges - Additional information (Detail) - USD ($)
$ in Millions
3 Months Ended 12 Months Ended
Mar. 31, 2017
Dec. 31, 2017
Asset Impairment Charges [Line Items]    
Asset impairment charge $ 3.2 $ 3.2
Definite-lived intangible assets 3.0  
Fixed Assets $ 0.2