Investment Securities - Contractual Maturities (Details) - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022
Available for Sale Securities, Amortized Cost
Within one year	$ 341,569	$ 118,984
After one through five years	134,187	203,236
Total, single maturity date	475,756	322,220
Total	689,842	337,387
Available for Sale Securities, Fair Value
Within one year	336,159	115,386
After one through five years	129,271	192,784
Total, single maturity date	465,430	308,170
Total	679,518	323,337
Held to Maturity Securities, Amortized Cost
Total	1,104,835	1,119,078
Held to Maturity Securities, Fair Value
Total	1,106,582	1,118,966
Held to maturity securities:
Amortized Cost	1,104,835	1,119,078
Fair Value	1,106,582	1,118,966
Mortgage-backed - Government-sponsored entity (GSE)
Available for Sale Securities, Amortized Cost
Without single maturity date	214,086	15,167
Total	214,086	15,167
Available for Sale Securities, Fair Value
Without single maturity date	214,088	15,167
Total	214,088	15,167
Held to Maturity Securities, Amortized Cost
Total	1,538	247,306
Held to Maturity Securities, Fair Value
Total	1,482	247,182
Held to maturity securities:
Amortized Cost	1,538	247,306
Fair Value	1,482	247,182
Mortgage-backed - Non-GSE multi-family
Held to Maturity Securities, Amortized Cost
Total	867,072	871,772
Held to Maturity Securities, Fair Value
Total	866,787	871,784
Held to maturity securities:
Amortized Cost	867,072	871,772
Fair Value	866,787	871,784
Mortgage-backed - Non-GSE residential
Held to Maturity Securities, Amortized Cost
Total	236,225	247,306
Held to Maturity Securities, Fair Value
Total	238,313	247,182
Held to maturity securities:
Amortized Cost	236,225	247,306
Fair Value	$ 238,313	$ 247,182