Fair Value Measurement - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
	Dec. 31, 2017	Jun. 30, 2018
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Goodwill Impairment		$ 3,400
Cloud Tv Reporting Unit
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Goodwill Impairment	$ 51,200	3,400
Cloud Tv Reporting Unit | Trade Names
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impairment of intangible assets	3,800
Non-controlling Interest | Cloud Tv Reporting Unit
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Goodwill Impairment		1,200
Impairment of intangible assets including goodwill	$ 19,300	$ 1,200