Commitments, Credit Risk And Contingencies (Summary of Off-Balance Sheet Credit Risk Information) (Details) (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jun. 30, 2011	Jun. 30, 2011 Commitments to Extend Credit [Member]	Dec. 31, 2010 Commitments to Extend Credit [Member]	Jun. 30, 2011 Standby Letters of Credit [Member]	Dec. 31, 2010 Standby Letters of Credit [Member]
Extended credit and standby letters of credit		$ 1,782,204	$ 1,550,256	$ 108,432	$ 101,185
Percentage of commitments to extend credit dependent upon the financial condition of the customers	78.50%