Property and Equipment - Additional information (Details) (USD $)
In Millions, unless otherwise specified |
12 Months Ended | ||
---|---|---|---|
Dec. 31, 2014
|
Dec. 31, 2013
|
Dec. 31, 2012
|
|
Property Plant And Equipment [Line Items] | |||
Depreciation expense | $ 18.7 | $ 17.0 | $ 13.0 |
Software Development | |||
Property Plant And Equipment [Line Items] | |||
Capitalized internal software development costs | $ 8.6 | $ 6.6 | $ 8.1 |