Basis of Presentation and Summary of Significant Accounting Policies (Equity Method and Cost Method Investments) (Details)	Dec. 31, 2018
Plural Editora e Grafica
Schedule of Equity Method Investments [Line Items]
Equity method investment, ownership percentage	49.00%
Maximum
Schedule of Equity Method Investments [Line Items]
Ownership percentage in investment required for equity method	50.00%
Ownership percentage in investment required for cost method (less than)	20.00%
Minimum
Schedule of Equity Method Investments [Line Items]
Ownership percentage in investment required for equity method	20.00%