Supplemental Condensed Consolidating Financial Information (Condensed Consolidating Balance Sheet Additional Information) (Detail) - USD ($) $ / shares in Units, $ in Thousands	Jun. 30, 2016	Dec. 31, 2015	May 13, 2011
Condensed Balance Sheet Statements, Captions [Line Items]
Allowance for doubtful accounts	$ 4,342	$ 4,923
Interest rate	7.75%	7.75%
Treasury stock, shares	22,449,496	22,445,945
Class A common stock
Condensed Balance Sheet Statements, Captions [Line Items]
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	750,000,000	750,000,000
Common stock, shares issued	256,248,431	255,902,892
Common stock, shares outstanding	233,798,935	233,456,945
Class C common stock
Condensed Balance Sheet Statements, Captions [Line Items]
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	644,871	644,871
Common stock, shares issued	644,871	644,871
Common stock, shares outstanding	644,871	644,871
7.75% senior notes:
Condensed Balance Sheet Statements, Captions [Line Items]
Interest rate	7.75%	7.75%	7.75%