Variable Interest Entities - Summary of Variable Interest Entities (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Variable Interest Entity [Line Items]
Investment securities available-for-sale, at fair value	$ 4,273,864	$ 3,931,115
Accrued expenses and other liabilities	203,962	243,207
Other assets	260,204	292,861
Assets	21,094,429	19,736,544
Liabilities	18,208,118	16,989,895
Variable Interest Entity, Not Primary Beneficiary
Variable Interest Entity [Line Items]
Maximum Loss	200,769	223,509
Assets	167,097	190,686
Liabilities	17,567	18,526
Variable Interest Entity, Not Primary Beneficiary | Multifamily Loan Securitization
Variable Interest Entity [Line Items]
Investment securities available-for-sale, at fair value	81,103	100,927
Accrued expenses and other liabilities	338	448
Variable Interest Entity, Not Primary Beneficiary | Multifamily Loan Securitization, Asset
Variable Interest Entity [Line Items]
Maximum Loss	81,103	100,927
Variable Interest Entity, Not Primary Beneficiary | Multifamily Loan Securitization, Liability
Variable Interest Entity [Line Items]
Maximum Loss	50,901	50,901
Variable Interest Entity, Not Primary Beneficiary | Affordable Housing Partnership
Variable Interest Entity [Line Items]
Accrued expenses and other liabilities	17,229	18,078
Other assets	85,994	89,759
Variable Interest Entity, Not Primary Beneficiary | Affordable Housing Partnership, Asset
Variable Interest Entity [Line Items]
Maximum Loss	68,765	71,681
Variable Interest Entity, Not Primary Beneficiary | Affordable Housing Partnership, Liability
Variable Interest Entity [Line Items]
Maximum Loss	$ 0	$ 0