Commitments, Off-Balance Sheet Arrangements and Contingent Liabilities (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013		Dec. 31, 2012
Commitments to Extend Credit [Member]
Summary of lending-related and other commitments
Lending related commitments	$ 6,367,771	[1],[2]	$ 5,526,326	[1],[2]
Commercial Letters Of Credit [Member]
Summary of lending-related and other commitments
Lending related commitments	132,777	[1]	85,689	[1]
Standby Letters of Credit [Member]
Summary of lending-related and other commitments
Lending related commitments	$ 250,030	[3]	$ 303,705	[3]

[1] These off-balance sheet financial instruments are exercisable at the market rate prevailing at the date the underlying transaction will be completed and, thus, are deemed to have no current fair value, or the fair value is based on fees currently charged to enter into similar agreements and is not material at December 31, 2013 or 2012.

[2] Interest rate lock commitments to originate residential mortgage loans held for sale are considered derivative instruments and are disclosed in Note 13.

[3] The Corporation has established a liability of $4 million at both December 31, 2013 and 2012, as an estimate of the fair value of these financial instruments.