Quarterly report pursuant to Section 13 or 15(d)

Acquisitions - Estimated Fair Values of Identifiable Intangible Assets and Related Weighted Average Amortization (Detail)

v3.10.0.1
Acquisitions - Estimated Fair Values of Identifiable Intangible Assets and Related Weighted Average Amortization (Detail) - USD ($)
$ in Thousands
6 Months Ended 12 Months Ended
Jun. 30, 2018
Jun. 30, 2018
Business Acquisition [Line Items]    
Estimated fair value at acquisition date   $ 116,600
Acquisitions 2018    
Business Acquisition [Line Items]    
Estimated fair value at acquisition date $ 19,836  
Weighted average amortization period at acquisition date 10 years 2 months  
Customer relationships | Acquisitions 2018    
Business Acquisition [Line Items]    
Estimated fair value at acquisition date $ 3,328  
Weighted average amortization period at acquisition date 5 years  
Backlog | Acquisitions 2018    
Business Acquisition [Line Items]    
Estimated fair value at acquisition date $ 1,055  
Weighted average amortization period at acquisition date 1 year  
Trade names | Acquisitions 2018    
Business Acquisition [Line Items]    
Estimated fair value at acquisition date $ 6,257  
Weighted average amortization period at acquisition date 15 years  
Non-compete agreements | Acquisitions 2018    
Business Acquisition [Line Items]    
Estimated fair value at acquisition date $ 196  
Weighted average amortization period at acquisition date 5 years  
Curriculum | Acquisitions 2018    
Business Acquisition [Line Items]    
Estimated fair value at acquisition date $ 9,000  
Weighted average amortization period at acquisition date 10 years