Investment Securities - Contractual Maturities (Details) - USD ($) $ in Thousands	Sep. 30, 2022	Dec. 31, 2021
Contractual Maturities, Amortized Cost
Total, single maturity date	$ 322,270	$ 277,502
Total	337,675	312,590
Contractual Maturities, Fair Value
Total, single maturity date	306,665	275,804
Total	322,069	310,629
Available for Sale Securities, Amortized Cost
Within one year	73,994	6,548
After one through five years	248,276	270,954
Total, single maturity date	322,270	277,502
Total	337,675	312,590
Available for Sale Securities, Fair Value
Within one year	71,805	6,551
After one through five years	234,860	269,253
Total, single maturity date	306,665	275,804
Total	322,069	310,629
Held to Maturity Securities, Amortized Cost
After one through five years	1,005,487
Total	1,005,487
Held to Maturity Securities, Fair Value
After one through five years	1,005,487
Total	1,005,487	0
Mortgage-backed - Government-sponsored entity (GSE)
Contractual Maturities, Amortized Cost
Without single maturity date	15,405	18,664
Total	15,405	18,664
Contractual Maturities, Fair Value
Without single maturity date	15,404	18,360
Total	15,404	18,360
Available for Sale Securities, Amortized Cost
Without single maturity date	15,405	18,664
Total	15,405	18,664
Available for Sale Securities, Fair Value
Without single maturity date	15,404	18,360
Total	15,404	18,360
Mortgage-backed - Non-GSE multi-family
Contractual Maturities, Amortized Cost
Without single maturity date		16,424
Total		16,424
Contractual Maturities, Fair Value
Without single maturity date		16,465
Total		16,465
Available for Sale Securities, Amortized Cost
Without single maturity date		16,424
Total		16,424
Available for Sale Securities, Fair Value
Without single maturity date		16,465
Total		$ 16,465
Held to Maturity Securities, Amortized Cost
Total	1,005,487
Held to Maturity Securities, Fair Value
Total	$ 1,005,487