Commitments and Contingencies - Additional Information (Detail) (USD $)
In Millions, unless otherwise specified |
12 Months Ended | ||
---|---|---|---|
Dec. 31, 2014
|
Dec. 31, 2013
|
Dec. 31, 2012
|
|
Commitments and Contingencies Disclosure [Abstract] | |||
Total rent expense | $ 7.6 | $ 7.3 | $ 6.9 |