Employee Benefit Plans (Weighted-Average Grant Date Fair Value Of Restricted Stock Awards) (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Employee Benefit Plans [Abstract]
Nonvested restricted stock, Shares, beginning balance	2,459
Nonvested restricted stock, Shares Granted	1,291
Nonvested restricted stock, Shares Vested	(584)
Nonvested restricted stock, Shares Forfeited	(250)
Nonvested restricted stock, Shares, ending balance	2,916	2,459
Nonvested restricted stock, Weighted-Average Grant-Date Fair Value, Beginning Balance	$ 51.38
Nonvested restricted stock, Weighted-Average Grant-Date Fair Value, Granted	$ 67.70	$ 49.29	$ 41.16
Nonvested restricted stock, Weighted-Average Grant-Date Fair Value, Vested	$ 67.87
Nonvested restricted stock, Weighted-Average Grant-Date Fair Value, Forfeited	$ 56.70
Nonvested restricted stock, Weighted-Average Grant-Date Fair Value, Ending Balance	$ 53.93	$ 51.38