Condensed Combined Debtors' Financial Information (Balance Sheet Additional Information) (Detail) - USD ($) $ / shares in Units, $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Allowance for doubtful accounts	$ 4,286	$ 4,322
Treasury stock, shares	2,806,187	2,806,187
Class A common stock
Common stock, par value (usd per share)	$ 0.01	$ 0.01
Common stock, shares authorized	93,750,000	93,750,000
Common stock, shares issued	32,031,952	32,031,952
Common stock, shares outstanding	29,225,765	29,225,765
Class C common stock
Common stock, par value (usd per share)	$ 0.01	$ 0.01
Common stock, shares authorized	80,609	80,609
Common stock, shares issued	80,609	80,609
Common stock, shares outstanding	80,609	80,609
Unconsolidated Subsidiaries
Allowance for doubtful accounts	$ 4,286
Treasury stock, shares	2,806,187
Unconsolidated Subsidiaries | Class A common stock
Common stock, par value (usd per share)	$ 0.01
Common stock, shares authorized	93,750,000
Common stock, shares issued	32,031,952
Common stock, shares outstanding	29,225,765
Unconsolidated Subsidiaries | Class C common stock
Common stock, par value (usd per share)	$ 0.01
Common stock, shares authorized	80,609
Common stock, shares issued	80,609
Common stock, shares outstanding	80,609