Stock-Based Compensation (Details Textual) (USD $)	1 Months Ended		3 Months Ended			12 Months Ended
	Dec. 31, 2009	Nov. 30, 2009	Apr. 03, 2011	Jul. 04, 2010	Dec. 31, 2009	Dec. 31, 2011 Year EmployeeGroup OptionPlan	Dec. 31, 2010	Dec. 31, 2009
Stock-Based Compensation Expense (Textual) [Abstract]
Shares available for grant under stock option plans						6,272,762
Outstanding shares in stock option		5,153,307
Minimum outstanding stock option exercise price		$ 23.00
Total shares purchased under option to purchase common stock	4,900,694
Stock option buyback	$ 9,158,000							$ (9,158,000)
Number of stock option plans						2
Weighted-average grant-date fair values of stock options granted						$ 12.32	$ 7.33	$ 5.42
Number of groups within the employee population						2
Percentage of stock options granted to senior management expected to vest						66.00%
Percentage of stock options granted to all other employees expected to vest						68.00%
Reduction in compensation expense due to revised estimated forfeiture rates			80,000	600,000
Estimated forfeiture rate for unvested options for senior management						13.00%
Estimated forfeiture rate for unvested options for all non-senior management						14.00%
Stock based compensation expense					2,657,000
Income tax benefit recognized related to stock-based compensation expense						2,660,000	996,000	3,070,000
Compensation expense capitalized						0	0
Total intrinsic values of stock options exercised						20,108,000	10,918,000	3,000
Total unrecognized compensation expense related to non-vested stock options						13,289,000
Weighted-average period for unrecognized compensation expense related to non-vested stock options (years)						1.7
Total fair values of stock options vested						10,202,000	13,159,000	14,177,000
Stock-based compensation expense						$ 8,068,000	$ 3,027,000	$ 9,223,000
Maximum [Member]
Stock-Based Compensation Expense (Textual) [Abstract]
Cash Payment for Eligible Options Under Tender Offer		$ 3.42
Minimum [Member]
Stock-Based Compensation Expense (Textual) [Abstract]
Cash Payment for Eligible Options Under Tender Offer		$ 0.05
General Stock Option Plan [Member]
Stock-Based Compensation Expense (Textual) [Abstract]
Shares available for grant under stock option plans						4,906,777
Expiration period of stock option plans						P10Y
Vesting period for stock option plans						4 years
Stock Option and Incentive Plan [Member]
Stock-Based Compensation Expense (Textual) [Abstract]
Shares available for grant under stock option plans						1,365,985
Expiration period of stock option plans						P10Y
Vesting period for stock option plans						4 years