Commitments, Off-Balance Sheet Arrangements and Contingent Liabilities (Details) (USD $) In Thousands	Jun. 30, 2011	Dec. 31, 2010
Commitments to Extend Credit [Member]
Summary of lending-related and other commitments
Lending related commitments	$ 4,019,334	$ 3,862,208
Commercial Letters Of Credit [Member]
Summary of lending-related and other commitments
Lending related commitments	44,582	37,872
Standby Letters of Credit [Member]
Summary of lending-related and other commitments
Lending related commitments	$ 326,408	$ 362,275