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Basis of Presentation - Additional Information (Detail)
$ in Millions
6 Months Ended
Jun. 30, 2017
USD ($)
Store
States
Basis Of Presentation [Line Items]  
Entity formed, year 1998
Number of Locations | Store 400
Number of states | States 40
Usual completion period for contracts with service elements 30 days
Compensation-Stock Compensation Codification  
Basis Of Presentation [Line Items]  
Recognized previously unrecorded windfall benefits | $ $ 8.9