Commitments and Contingencies (Narrative) (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Commitments to Extend Credit
Letters of credit	$ 2,220,000	$ 2,240,000
Allowance for Unfunded Credit Commitments	27,500	33,500
Other Commitments
Total	309,616
Accrued Expenses And Other Liabilities
Other Commitments
Total	309,600	182,700
Standby Letters of Credit
Commitments to Extend Credit
Letters of credit	2,140,000	2,120,000
Commercial Letters Of Credit
Commitments to Extend Credit
Letters of credit	78,900	124,900
Loans sold or securitized with recourse | Single Family Residential and Multi-Family Residential | Loans Sold or Securitized with Recourse
Commitments to Extend Credit
Allowance for Unfunded Credit Commitments	$ 29	$ 88