Significant Accounting Policies (Share-Based Compensation Expense) (Details) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Summary of Significant Accounting Policies [Abstract]
Share-based compensation expense	$ 28,893,000	$ 27,602,000	$ 33,112,000
Employee Service Share-based Compensation, Tax Benefit from Compensation Expense	11,200,000	10,700,000	12,800,000
Excess tax benefit on share-based compensation	$ 6,089,000	$ 1,349,000	$ 571,000