Share Repurchases (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	1 Months Ended	3 Months Ended
	Oct. 31, 2010 Y	Mar. 31, 2012	Apr. 02, 2011
Share Repurchases
Cumulative balance, Shares, Beginning Balance		35,643	23,713
Cumulative balance, Weighted Average Price Per Share, Beginning Balance		$ 16.96	$ 16.40
Cumulative balance, Amount, Beginning Balance		$ 604,331	$ 388,817
Repurchase of Class A Common Stock, Shares			46
Repurchase of Class A Common Stock, Weighted Average Price Per Share			$ 19.49
Repurchase of Class A Common Stock, Amount			906
Issuance of Class A Common Stock, Shares		(293)	(479)
Issuance of Class A Common Stock, Weighted Average Price Per Share		$ 18.45	$ 19.01
Issuance of Class A Common Stock, Amount		(5,397)	(9,121)
Cumulative balance, Shares, Ending Balance		35,350	23,280
Cumulative balance, Weighted Average Price Per Share, Ending Balance		$ 16.94	$ 16.35
Cumulative balance, Amount, Ending Balance		598,934	380,602
Share repurchases (Textual) [Abstract]
Remaining amount for repurchase under the share repurchase program		174,095
Shares authorized for repurchase program	$ 400,000
Duration of new share repurchase program (in years)	3