Shareholders' Equity And Earnings Per Share (Aggregate Fair Values Assigned To Each Component Of Tangible Equity Units) (Details) (USD $) In Thousands, except Share data, unless otherwise specified	6 Months Ended
	Jun. 30, 2011		Dec. 31, 2010
Units issued	4,600	[1]
Unit price	50.000000		50.00
Gross proceeds	$ 230,000
Issuance costs, including discount	7,353
Net proceeds	222,647
Other Borrowings [Member]
Net proceeds	(43,331)
Other Borrowings [Member] | Debt Component [Member]
Net proceeds	(43,331)
Equity Component [Member] | Surplus [Member]
Net proceeds	179,316
Surplus [Member]
Net proceeds	179,316
Equity Component [Member]
Units issued	4,600	[1]
Unit price	40.271818
Gross proceeds	185,250
Issuance costs, including discount	5,934
Net proceeds	179,316
Debt Component [Member]
Units issued	4,600	[1]
Unit price	9.728182
Gross proceeds	44,750
Issuance costs, including discount	1,419
Net proceeds	$ 43,331

[1] Each TEU consists of two components: 4.6 million units of the equity component and 4.6 million units of the debt component.