Subsequent Event - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands	Jul. 05, 2018	Jun. 30, 2018
Subsequent Event [Line Items]
Interest in common units of NCM owned by Company		18.00%
NCM
Subsequent Event [Line Items]
Interest in common units of NCM owned by Company		18.00%
NCM | Subsequent Event
Subsequent Event [Line Items]
Number of common units of NCM acquired by Company	10,738,740
Value of common units in cash	$ 78,400
Common unit price per share	$ 7.30
Interest in common units of NCM owned by Company	25.00%