Commitments, Off-Balance Sheet Arrangements, and Contingent Liabilities, Summary of Lending Related and Other Commitments (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Summary of lending-related and other commitments
Standby letters of credit, fair value	$ 2,954	$ 3,542
Commitments to extend credit, excluding commitments to originate residential mortgage loans held for sale [Member]
Summary of lending-related and other commitments
Lending related commitments	7,402,518	6,884,411
Commercial Letters Of Credit [Member]
Summary of lending-related and other commitments
Lending related commitments	9,945	9,179
Standby Letters of Credit [Member]
Summary of lending-related and other commitments
Lending related commitments	296,508	353,292
Standby letters of credit, fair value	$ 3,000	$ 4,000