Stock-Based Compensation (Details 8) (USD $)	0 Months Ended		3 Months Ended		6 Months Ended		0 Months Ended				3 Months Ended		6 Months Ended		3 Months Ended		6 Months Ended		3 Months Ended		6 Months Ended		3 Months Ended	6 Months Ended
	Dec. 28, 2012	Dec. 02, 2011	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012	Dec. 28, 2012 Class A common stock	Dec. 02, 2011 Class A common stock	Dec. 28, 2012 Class B common stock	Dec. 02, 2011 Class B common stock	Jun. 30, 2013 Stock options	Jun. 30, 2012 Stock options	Jun. 30, 2013 Stock options	Jun. 30, 2012 Stock options	Jun. 30, 2013 Stock options Minimum	Jun. 30, 2012 Stock options Minimum	Jun. 30, 2013 Stock options Minimum	Jun. 30, 2012 Stock options Minimum	Jun. 30, 2013 Stock options Maximum	Jun. 30, 2012 Stock options Maximum	Jun. 30, 2013 Stock options Maximum	Jun. 30, 2012 Stock options Maximum	Mar. 31, 2013 Stock option adjustment 2012	Jun. 30, 2013 Stock option adjustment 2012
Stock-Based Compensation
Non-cash, stock-based compensation			$ 4,042,000	$ 7,017,000	$ 15,362,000	$ 30,199,000																	$ 5,000,000
Black-Scholes option valuation model, assumptions
Risk free interest rate, low end of range (as a percent)											0.91%	0.41%	0.91%	0.41%
Risk free interest rate, high end of range (as a percent)											1.86%	0.87%	1.93%	1.29%
Volatility factor, low end of range (as a percent)											32.44%	33.15%	32.37%	33.15%
Volatility factor, high end of range (as a percent)											39.87%	38.87%	39.87%	39.34%
Expected term of options															5 years 8 months 12 days	3 years 1 month 6 days	5 years 8 months 12 days	3 years 1 month 6 days	9 years 9 months 18 days	5 years 9 months 18 days	10 years	5 years 10 months 24 days
Weighted-average fair value of options granted (in dollars per share)															$ 14.49	$ 6.72	$ 14.49	$ 6.72	$ 16.85	$ 10.72	$ 16.85	$ 12.69
Dividend in cash per share							$ 1.00	$ 2.00	$ 1.00	$ 2.00
Adjustment to recognized non-cash, stock-based compensation expense to be expensed over the remaining vesting period																								$ 3,000,000
Dividend yield (as a percent)	0.00%	0.00%