XML 74 R64.htm IDEA: XBRL DOCUMENT v3.10.0.1
Goodwill - Additional Information (Details)
Patient in Millions
 12 Months Ended
Jul. 27, 2017
USD ($)
Sep. 15, 2016
USD ($)
Dec. 04, 2015
USD ($)
Patient
Site
Dec. 31, 2017
USD ($)
Dec. 31, 2018
USD ($)
Jun. 30, 2017
USD ($)
Mar. 31, 2017
USD ($)
Dec. 31, 2016
USD ($)
Business Acquisition [Line Items]                
Goodwill       $ 769,058,000 $ 756,260,000     $ 616,088,000
Mapi Development SAS                
Business Acquisition [Line Items]                
Goodwill       130,300,000        
Mapi Group                
Business Acquisition [Line Items]                
Goodwill $ 130,270,000              
Consideration transferred 145,776,000              
Working capital adjustment $ 1,645,000              
ICON Government & Public Health Solutions                
Business Acquisition [Line Items]                
Goodwill   $ 35,969,000            
Consideration transferred   58,396,000            
Net cash outflows   52,400,000            
Other liabilities assumed   9,200,000            
Maximum additional consideration that might be payable   $ 12,000,000.0            
Assessment of valuation of contingent consideration at acquisition           $ 0 $ 6,000,000  
PMG                
Business Acquisition [Line Items]                
Consideration transferred     $ 65,400,000          
Other liabilities assumed     $ 10,100,000          
Number of clinical research sites acquired | Site     52          
Number of active patients via electronic medical records acquired (in excess of) | Patient     2          
Selling, general and administrative | ICON Government & Public Health Solutions                
Business Acquisition [Line Items]                
Decrease in amount of contingent consideration, liability       $ 6,000,000