Commitments and Contingencies - Narrative (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Commitments to Extend Credit
Letters of credit	$ 2,530,000	$ 2,290,000
Allowance for unfunded credit commitments	33,600	26,200
Loans Sold or Securitized With Recourse | Single Family and Multi-family Residential Loans | Loans Sold or Securitized with Recourse
Commitments to Extend Credit
Allowance for unfunded credit commitments	35	37
Standby Letters of Credit
Commitments to Extend Credit
Letters of credit	2,500,000	2,270,000
Commercial Letters of Credit
Commitments to Extend Credit
Letters of credit	$ 32,700	$ 21,600