Loans - Composition of Loans (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Loans:
Net unamortized premiums and unearned loan fees	$ 9,059	$ 9,011
Total loans, net of fees and costs excluding portfolio layer basis adjustments	6,906,713	6,934,769
Unallocated portfolio layer basis adjustments	(10,639)
Total loans, net of fees and costs	6,896,074	6,934,769
Multi-Family Residential
Loans:
Loans before allowance for credit losses, fee and costs	2,614,219	2,601,384
Commercial Real Estate
Loans:
Loans before allowance for credit losses, fee and costs	1,953,243	1,913,040
One-To-Four Family - Mixed Used Property
Loans:
Loans before allowance for credit losses, fee and costs	537,744	554,314
One-To-Four Family - Residential
Loans:
Loans before allowance for credit losses, fee and costs	222,874	241,246
Construction Portfolio Segment
Loans:
Loans before allowance for credit losses, fee and costs	59,903	70,951
Total loans, net of fees and costs excluding portfolio layer basis adjustments	59,775	70,824
Small Business Administration
Loans:
Loans before allowance for credit losses, fee and costs	21,896	23,275
Commercial Business and Other
Loans:
Loans before allowance for credit losses, fee and costs	$ 1,487,775	$ 1,521,548