Basis of Presentation and Significant Accounting Policies - Schedule of Changes in Carrying Amount of Goodwill (Details) (USD $)
In Thousands, unless otherwise specified
3 Months Ended
Mar. 31, 2015
Goodwill [Roll Forward]  
Goodwill - beginning balance $ 408,988
Goodwill acquired during 2015 21,088
Adjustment for prior year transactions (283)
Goodwill - ending balance $ 429,793