Investment Securities, Contractual Maturity (Details) - USD ($) $ in Thousands		Dec. 31, 2021	Dec. 31, 2020
Amortized Cost [Abstract]
One year or less		$ 5,430
After one year through five years		5,094
After five years through ten years		510
After ten years		5,690
Amortized cost, excluding securities without single maturity date		16,724
Amortized cost		272,436	$ 789,175
Fair Value [Abstract]
One year or less		5,465
After one year through five years		5,209
After five years through ten years		512
After ten years		5,711
Fair value, excluding investment securities not due at a single maturity date		16,897
Fair value		270,454	807,732
Amortized Cost [Abstract]
One year or less		308
After one year through five years		8,487
After five years through ten years		18,433
After ten years		39,268
Fair value, excluding securities without single maturity date		66,496
Amortized cost		737,052	68,933
Fair Value [Abstract]
One year or less		308
After one year through five years		8,528
After five years through ten years		19,072
After ten years		39,288
Fair value, excluding securities without single maturity date		67,196
Fair value		725,841	70,049
Mortgage-backed Securities [Member]
Amortized Cost [Abstract]
Securities not due at a single maturity date		253,300
Amortized cost	[1]	253,300	715,523
Fair Value [Abstract]
Securities not due at a single maturity date		251,120
Fair value	[1]	251,120	732,720
Amortized Cost [Abstract]
Securities not due at a single maturity date		596,775
Amortized cost	[1]	596,775
Fair Value [Abstract]
Securities not due at a single maturity date		585,056
Fair value	[1]	585,056
Collateralized Mortgage Obligations [Member]
Amortized Cost [Abstract]
Securities not due at a single maturity date		2,412
Amortized cost		2,412	5,039
Fair Value [Abstract]
Securities not due at a single maturity date		2,437
Fair value		2,436	$ 5,153
Amortized Cost [Abstract]
Securities not due at a single maturity date		73,781
Amortized cost		73,781
Fair Value [Abstract]
Securities not due at a single maturity date		73,589
Fair value		$ 73,588

[1] All mortgage-backed securities were issued by an agency or government sponsored entity of the U.S. Government.