Annual report pursuant to Section 13 and 15(d)

Summary of Significant Accounting Policies - Summary of Intangibles are Amortized Using the Straight-line Method over Estimated Useful Lives (Detail)

v3.19.1
Summary of Significant Accounting Policies - Summary of Intangibles are Amortized Using the Straight-line Method over Estimated Useful Lives (Detail)
 12 Months Ended
Dec. 31, 2018
Customer Lists and Contracts [Member]  
Finite-Lived Intangible Assets [Line Items]  
Estimated useful life of intangible assets, description Lesser of 5 years or the life of contract
Favorable and Assigned Leases [Member]  
Finite-Lived Intangible Assets [Line Items]  
Estimated useful life of intangible assets, description Lease Term
Minimum [Member] | Domain and Brand Names [Member]  
Finite-Lived Intangible Assets [Line Items]  
Estimated useful life of intangible assets 5 years
Minimum [Member] | Subscriber Base and Lists [Member]  
Finite-Lived Intangible Assets [Line Items]  
Estimated useful life of intangible assets 3 years
Minimum [Member] | Author Relationships [Member]  
Finite-Lived Intangible Assets [Line Items]  
Estimated useful life of intangible assets 1 year
Minimum [Member] | Non-Compete Agreements [Member]  
Finite-Lived Intangible Assets [Line Items]  
Estimated useful life of intangible assets 1 year
Maximum [Member] | Domain and Brand Names [Member]  
Finite-Lived Intangible Assets [Line Items]  
Estimated useful life of intangible assets 7 years
Maximum [Member] | Subscriber Base and Lists [Member]  
Finite-Lived Intangible Assets [Line Items]  
Estimated useful life of intangible assets 7 years
Maximum [Member] | Author Relationships [Member]  
Finite-Lived Intangible Assets [Line Items]  
Estimated useful life of intangible assets 7 years
Maximum [Member] | Non-Compete Agreements [Member]  
Finite-Lived Intangible Assets [Line Items]  
Estimated useful life of intangible assets 5 years