Commitments and Contingencies (Details) $ in Thousands	Jun. 30, 2019 USD ($) Advances	Dec. 31, 2018 USD ($)
Guarantor Obligations [Line Items]
FDIC shared-loss payable	$ 108,892	$ 105,618
Number Of Federal Home Loan Bank Advances | Advances
Standby Letters of Credit
Guarantor Obligations [Line Items]
Guarantor Obligations, Maximum Exposure, Undiscounted	$ 170,300	147,300
Commitments to Extend Credit
Guarantor Obligations [Line Items]
Unused Commitments to Extend Credit	10,348,284	10,054,712
Qualified Affordable Housing Project Investments, Commitment	94,307	96,467
Qualified Affordable Housing Project Investments	$ 80,383	$ 67,952