Commitments and Contingencies (Narrative) (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Commitments to Extend Credit
Letters of credit	$ 2,210,000	$ 2,220,000
Allowance for unfunded credit commitments	23,200	27,500
Accrued expenses and other liabilities
Other Commitments
Unfunded commitments for investments in AHP and other tax credit investments	288,200	309,600
Single Family and Multi-family Residential Loans | Loans Sold or Securitized with Recourse | Loans Sold or Securitized With Recourse
Commitments to Extend Credit
Allowance for unfunded credit commitments	23	29
Standby Letters of Credit
Commitments to Extend Credit
Letters of credit	2,160,000	2,140,000
Commercial Letters of Credit
Commitments to Extend Credit
Letters of credit	$ 53,600	$ 78,900