Annual report pursuant to Section 13 and 15(d)

Goodwill and Intangible Assets (Intangible Assets) (Details)

v3.10.0.1
Goodwill and Intangible Assets (Intangible Assets) (Details) - USD ($)
 12 Months Ended
Dec. 31, 2018
Dec. 31, 2017
Dec. 31, 2016
Components of intangible assets      
Gross Carrying Amount $ 466,756,000 $ 352,567,000  
Accumulated Amortization (161,515,000) (129,836,000)  
Net Carrying Amount 305,241,000 222,731,000  
Write-off of fully amortized intangible assets 22,177,000 0  
Amortization expense 53,856,000 42,127,000 $ 45,515,000
Customer lists      
Components of intangible assets      
Gross Carrying Amount 361,020,000 259,350,000  
Accumulated Amortization (102,077,000) (78,482,000)  
Net Carrying Amount $ 258,943,000 180,868,000  
Customer lists | Minimum      
Components of intangible assets      
Estimated Useful Life 7 years    
Customer lists | Maximum      
Components of intangible assets      
Estimated Useful Life 15 years    
Proprietary technologies      
Components of intangible assets      
Gross Carrying Amount $ 66,746,000 57,377,000  
Accumulated Amortization (36,151,000) (31,067,000)  
Net Carrying Amount $ 30,595,000 26,310,000  
Proprietary technologies | Minimum      
Components of intangible assets      
Estimated Useful Life 4 years    
Proprietary technologies | Maximum      
Components of intangible assets      
Estimated Useful Life 8 years    
Trade names      
Components of intangible assets      
Gross Carrying Amount $ 27,990,000 24,840,000  
Accumulated Amortization (12,352,000) (9,701,000)  
Net Carrying Amount $ 15,638,000 15,139,000  
Trade names | Minimum      
Components of intangible assets      
Estimated Useful Life 2 years    
Trade names | Maximum      
Components of intangible assets      
Estimated Useful Life 7 years    
Backlog      
Components of intangible assets      
Estimated Useful Life 4 years    
Gross Carrying Amount $ 11,000,000 11,000,000  
Accumulated Amortization (10,935,000) (10,586,000)  
Net Carrying Amount $ 65,000 $ 414,000