Investment Securities, Securities Held-to-Maturity (Details) - USD ($) $ in Thousands		Sep. 30, 2022	Dec. 31, 2021
Book values, estimated fair values and unrealized gains and losses of investments classified as held-to-maturity [Abstract]
Amortized cost		$ 852,665	$ 737,052
Gross unrealized gains		0	782
Gross unrealized losses		161,743	11,993
Fair value		690,922	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		60,827	66,496
Gross unrealized gains		0	701
Gross unrealized losses		735	0
Fair value		60,092	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]	709,541	596,775
Gross unrealized gains	[1]	0	45
Gross unrealized losses	[1]	145,836	11,764
Fair value	[1]	563,705	585,056
Allowance for credit losses	[1]	0	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]	82,297	73,781
Gross unrealized gains	[1]	0	36
Gross unrealized losses	[1]	15,172	229
Fair value	[1]	67,125	73,588
Allowance for credit losses	[1]	$ 0	$ 0

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