Depreciation and Amortization Expense Related to Property and Equipment (Detail) - USD ($) $ in Thousands |
3 Months Ended | 9 Months Ended | ||
---|---|---|---|---|
Sep. 30, 2015 |
Sep. 30, 2014 |
Sep. 30, 2015 |
Sep. 30, 2014 |
|
Property, Plant and Equipment [Line Items] | ||||
Depreciation and amortization expense | $ 3,165 | $ 2,449 | $ 8,282 | $ 4,972 |