Variable Interest Entities - Summary (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Variable Interest Entity [Line Items]
Investment securities available-for-sale	$ 3,222,095	$ 4,273,864
Accrued expenses and other liabilities	219,329	203,962
Other assets	242,916	260,204
Assets	21,622,296	21,094,429
Liabilities	18,839,278	18,208,118
Variable Interest Entity, Not Primary Beneficiary
Variable Interest Entity [Line Items]
Maximum Loss	194,701	200,769
Assets	160,671	167,097
Liabilities	17,209	17,567
Variable Interest Entity, Not Primary Beneficiary | Multifamily Loan Securitization
Variable Interest Entity [Line Items]
Investment securities available-for-sale	77,939	81,103
Accrued expenses and other liabilities	338	338
Variable Interest Entity, Not Primary Beneficiary | Multifamily Loan Securitization, Asset
Variable Interest Entity [Line Items]
Maximum Loss	77,939	81,103
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	16,871	17,229
Other assets	82,732	85,994
Variable Interest Entity, Not Primary Beneficiary | Affordable Housing Partnership, Asset
Variable Interest Entity [Line Items]
Maximum Loss	65,861	68,765
Variable Interest Entity, Not Primary Beneficiary | Affordable Housing Partnership, Liability
Variable Interest Entity [Line Items]
Maximum Loss	$ 0	$ 0