Commitments and Contingencies (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Guarantor Obligations [Line Items]
Amortization Method Qualified Affordable Housing Project Investments	$ 147,300	$ 128,000
FDIC shared-loss payable	105,618	101,342	$ 97,008
Commitments to Extend Credit
Guarantor Obligations [Line Items]
Unused Commitments to Extend Credit	10,054,712	9,629,365
Affordable Housing Program Obligation	67,952	61,819
Standby Letters of Credit
Guarantor Obligations [Line Items]
Guarantor obligations amount	$ 96,467	81,530
Obligation to Repurchase Receivables Sold
Guarantor Obligations [Line Items]
Reserve for estimated losses arising from repurchase of loans		$ 882