Variable Interest Entities - Summary (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Variable Interest Entity [Line Items]
AFS investment securities	$ 1,914,599	$ 2,601,013
Accrued expenses and other liabilities	281,057	206,023
Other assets	297,574	253,871
Assets	20,275,720	21,688,017
Liabilities	17,420,186	18,889,628
Variable Interest Entity, Not Primary Beneficiary
Variable Interest Entity [Line Items]
Maximum Loss	158,305	168,216
Assets	143,322	132,743
Liabilities	36,251	15,762
Variable Interest Entity, Not Primary Beneficiary | Multifamily Loan Securitization, Asset
Variable Interest Entity [Line Items]
Maximum Loss	51,055	56,784
AFS investment securities	51,055	56,784
Variable Interest Entity, Not Primary Beneficiary | Multifamily Loan Securitization, Liability
Variable Interest Entity [Line Items]
Maximum Loss	50,901	50,901
Accrued expenses and other liabilities	334	334
Variable Interest Entity, Not Primary Beneficiary | Affordable Housing Partnership, Asset
Variable Interest Entity [Line Items]
Maximum Loss	56,349	60,531
Other assets	92,267	75,959
Variable Interest Entity, Not Primary Beneficiary | Affordable Housing Partnership, Liability
Variable Interest Entity [Line Items]
Maximum Loss	0	0
Accrued expenses and other liabilities	$ 35,917	$ 15,428