Investment Securities, Securities Held-to-Maturity (Details) - USD ($) $ in Thousands		Dec. 31, 2022		Dec. 31, 2021
Book values, estimated fair values and unrealized gains and losses of investments classified as held-to-maturity [Abstract]
Amortized cost		$ 845,346		$ 737,052
Gross unrealized gains		78		782
Gross unrealized losses		157,031		11,993
Fair value		688,393		725,841
Allowance for credit losses		393		0
Municipal Securities [Member]
Book values, estimated fair values and unrealized gains and losses of investments classified as held-to-maturity [Abstract]
Amortized cost		62,302		66,496
Gross unrealized gains		49		701
Gross unrealized losses		209		0
Fair value		62,142		67,197
Allowance for credit losses		393		0
Mortgage-backed Securities [Member]
Book values, estimated fair values and unrealized gains and losses of investments classified as held-to-maturity [Abstract]
Amortized cost	[1]	702,858		596,775
Gross unrealized gains	[1]	29		45
Gross unrealized losses	[1]	141,121		11,764
Fair value	[1]	561,766		585,056
Allowance for credit losses		0	[1]	0
Collateralized Mortgage Obligations [Member]
Book values, estimated fair values and unrealized gains and losses of investments classified as held-to-maturity [Abstract]
Amortized cost	[1]	80,186		73,781
Gross unrealized gains	[1]	0		36
Gross unrealized losses	[1]	15,701		229
Fair value	[1]	64,485		73,588
Allowance for credit losses		$ 0	[1]	$ 0

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