Loans - Loans Sales (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total net gains on loan sales	$ 9,977	$ 2,629
Corporate Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Payments for loan purchases	175,225	146,461
Corporate Loans | Multi-family
Accounts, Notes, Loans and Financing Receivable [Line Items]
Payments for loan purchases	14,249	0
Consumer Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Payments for loan purchases	467,857	215,142
Corporate loan sales
Accounts, Notes, Loans and Financing Receivable [Line Items]
Proceeds from sales	16,936	4,303
Less book value of loans sold	16,891	4,188
Total net gains on loan sales	45	115
Commercial and industrial | Corporate Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Payments for loan purchases	153,396	145,822
Office, retail, and industrial | Corporate Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Payments for loan purchases	7,438	0
Construction | Corporate Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Payments for loan purchases	142	639
Home equity | Consumer Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Payments for loan purchases	0	144,967
1-4 family mortgages
Accounts, Notes, Loans and Financing Receivable [Line Items]
Proceeds from sales	293,830	119,159
Less book value of loans sold	283,898	116,645
Total net gains on loan sales	9,932	2,514
1-4 family mortgages | Consumer Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Payments for loan purchases	361,099	70,175
Installment | Consumer Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Payments for loan purchases	$ 106,758	$ 0