Stockholders' Equity (Details Textuals) (USD $) In Thousands, except Share data	1 Months Ended	3 Months Ended		6 Months Ended
	Aug. 02, 2011	Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010
Stockholders' Equity (Textuals) [Abstract]
Maximum shares authorized for repurchase				30,000,000
Stock repurchased, shares	600,000			0
Additional shares authorized for repurchase	1,400,000			2,000,000
Treasury stock issued to accommodate employee stock option exercises				1,719,000
Lower limit of exercise price of stock options				$ 10.50
Upper limit of exercise price of stock options				$ 36.64
Proceeds from stock option exercises				$ 33,022	$ 7,409
Deferred tax benefit (expense)		2,029	3,404	2,702	631
Deferred tax benefit (expense)		$ 146	$ 96	$ 186	$ 127