Stockholders' Equity - Share-based Compensation Plans (Detail) (USD $)	12 Months Ended									1 Months Ended
	Dec. 31, 2012 plans		Dec. 31, 2012 Employee Stock Option	Dec. 31, 2011 Employee Stock Option	Dec. 31, 2010 Employee Stock Option	Dec. 31, 2012 2012 Plan	Dec. 31, 2012 2012 Plan Min	Dec. 31, 2012 2012 Plan Max	Dec. 31, 2012 2005 Officer's Stock Plan	Nov. 30, 2005 2005 Officer's Stock Plan Class B Common Stock
Share-based Compensation Arrangement by Share-based Payment Award
Share-based employee compensation plans, number	3
2012 Equity Incentive Plan shares authorized	25,000,000	[1]				25,000,000
Shares reserved for issuance increase date range							Jan. 01, 2013	Jan. 01, 2022
Shares reserved for issuance increase percentage						2.50%
Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period						10 years
Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period for Plan						10 years			10 years
Shares of incentive and nonstatutory stock options provided for issuance									120,000,000
Non statutory stock option issued to CEO to purchase shares of Class B common stock										120,000,000
Options partially exercised and fully vested									60,000,000
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions and Methodology [Abstract]
Expected term from grant date (in years)					7 years 1 month 24 days
Risk-free interest rate					1.69%
Expected volatility					46.00%
Dividend yield					0.00%
Weighted-average fair value of employee options granted			$ 0.00	$ 0.00	$ 5.26

[1] After excluding 195 thousand restricted stock awards included in the table above, 171,796 thousand shares are available for grant under the Stock Plans as of December 31, 2012.