Leases - Additional Information (Detail) - USD ($) $ in Millions |
12 Months Ended | ||
---|---|---|---|
Dec. 31, 2016 |
Dec. 31, 2015 |
Dec. 31, 2014 |
|
Operating Leased Assets [Line Items] | |||
Rent expense | $ 7.0 | $ 6.0 | $ 5.2 |
Minimum [Member] | |||
Operating Leased Assets [Line Items] | |||
Lease extension period | 1 year | ||
Maximum [Member] | |||
Operating Leased Assets [Line Items] | |||
Lease extension period | 10 years |