Commitments and Contingencies Commitments (Details) $ in Thousands	Jun. 30, 2020 USD ($)
Lending related commitments [Line Items]
Unused Commitments to Extend Credit	$ 4,737,853
Loan Origination Commitments [Member]
Lending related commitments [Line Items]
Unused Commitments to Extend Credit	770,860
Loan Purchase Commitments [Member]
Lending related commitments [Line Items]
Unused Commitments to Extend Credit	733,451
Unused lines of Credit [Member]
Lending related commitments [Line Items]
Unused Commitments to Extend Credit	3,145,104
Standby Letters of Credit [Member]
Lending related commitments [Line Items]
Unused Commitments to Extend Credit	$ 88,438