Segment Reporting - Additional Information (Detail) (USD $)
In Thousands, unless otherwise specified
3 Months Ended
Mar. 31, 2015
Segment
Mar. 31, 2014
Dec. 31, 2014
Segment Reporting Information [Line Items]      
Number of reportable segments 2    
Revenues $ 132,629 $ 102,404  
Assets 2,030,944   2,103,174
United States      
Segment Reporting Information [Line Items]      
Revenues 110,500 81,100  
Assets $ 1,700,000   $ 1,700,000