Fair Value Measurements, Assets and Liabilities Measured at Fair Value on a Recurring Basis (Details) - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Assets, Fair Value Disclosure [Abstract]
AFS investment securities, at fair value	$ 3,381,607	$ 2,742,025
Equity securities with readily determinable fair values, Fair Value	6,000	6,000
Servicing Asset at Fair Value, Amount	74,479	77,351	$ 57,158
Fair Value, Inputs, Level 1
Assets, Fair Value Disclosure [Abstract]
AFS investment securities, at fair value	111,743	109,378
Equity securities with readily determinable fair values, Fair Value	6,286	5,991
Fair Value, Inputs, Level 2
Assets, Fair Value Disclosure [Abstract]
AFS investment securities, at fair value	3,269,864	2,632,647
Fair Value, Inputs, Level 3
Assets, Fair Value Disclosure [Abstract]
Servicing Asset at Fair Value, Amount	74,479	77,351
Liabilities, Fair Value Disclosure [Abstract]
Trading liabilities	441	46
Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 2 | Designated as Hedging Instrument
Assets, Fair Value Disclosure [Abstract]
Interest Rate Fair Value Hedge Asset at Fair Value	19,416	4,349
Liabilities, Fair Value Disclosure [Abstract]
Interest Rate Fair Value Hedge Liability at Fair Value	0	1,260
Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 3
Assets, Fair Value Disclosure [Abstract]
Servicing Asset at Fair Value, Amount	74,479	77,351
US Treasury Securities
Assets, Fair Value Disclosure [Abstract]
AFS investment securities, at fair value	111,743	109,378
US Treasury Securities | Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 1
Assets, Fair Value Disclosure [Abstract]
AFS investment securities, at fair value	111,743	109,378
Agency Securities
Assets, Fair Value Disclosure [Abstract]
AFS investment securities, at fair value	13,730	13,532
Agency Securities | Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 2
Assets, Fair Value Disclosure [Abstract]
AFS investment securities, at fair value	13,730	13,532
US States and Political Subdivisions Debt Securities [Member]
Assets, Fair Value Disclosure [Abstract]
AFS investment securities, at fair value	228,902	230,714
US States and Political Subdivisions Debt Securities [Member] | Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 2
Assets, Fair Value Disclosure [Abstract]
AFS investment securities, at fair value	228,902	230,714
Mortgage-backed Securities, Issued by Private Enterprises [Member]
Assets, Fair Value Disclosure [Abstract]
AFS investment securities, at fair value	0
Residential Related Securities | FNMA/FHLMC
Assets, Fair Value Disclosure [Abstract]
AFS investment securities, at fair value	1,574,578	1,604,610
Residential Related Securities | FNMA/FHLMC | Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 2
Assets, Fair Value Disclosure [Abstract]
AFS investment securities, at fair value	1,574,578	1,604,610
Residential Related Securities | Government National Mortgage Association (GNMA) [Member]
Assets, Fair Value Disclosure [Abstract]
AFS investment securities, at fair value	1,095,588	497,596
Residential Related Securities | Government National Mortgage Association (GNMA) [Member] | Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 2
Assets, Fair Value Disclosure [Abstract]
AFS investment securities, at fair value	1,095,588	497,596
Commercial mortgage-related securities | FNMA/FHLMC
Assets, Fair Value Disclosure [Abstract]
AFS investment securities, at fair value	17,618	17,142
Commercial mortgage-related securities | FNMA/FHLMC | Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 2
Assets, Fair Value Disclosure [Abstract]
AFS investment securities, at fair value	17,618	17,142
Commercial mortgage-related securities | Government National Mortgage Association (GNMA) [Member]
Assets, Fair Value Disclosure [Abstract]
AFS investment securities, at fair value	189,466	110,462
Commercial mortgage-related securities | Government National Mortgage Association (GNMA) [Member] | Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 2
Assets, Fair Value Disclosure [Abstract]
AFS investment securities, at fair value	189,466	110,462
Federal Family Education Loan Program (FFELP) Guaranteed Loans [Member]
Assets, Fair Value Disclosure [Abstract]
AFS investment securities, at fair value	143,084	151,191
Federal Family Education Loan Program (FFELP) Guaranteed Loans [Member] | Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 2
Assets, Fair Value Disclosure [Abstract]
AFS investment securities, at fair value	143,084	151,191
US Government-sponsored Enterprises Debt Securities [Member]
Assets, Fair Value Disclosure [Abstract]
AFS investment securities, at fair value	3,983	4,477
US Government-sponsored Enterprises Debt Securities [Member] | Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 2
Assets, Fair Value Disclosure [Abstract]
AFS investment securities, at fair value	3,983	4,477
Other Debt securities
Assets, Fair Value Disclosure [Abstract]
AFS investment securities, at fair value	2,918	2,922
Other Debt securities | Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 2
Assets, Fair Value Disclosure [Abstract]
AFS investment securities, at fair value	2,918	2,922
Available-for-sale Securities [Member] | Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 1
Assets, Fair Value Disclosure [Abstract]
AFS investment securities, at fair value	111,743	109,378
Available-for-sale Securities [Member] | Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 2
Assets, Fair Value Disclosure [Abstract]
AFS investment securities, at fair value	3,269,864	2,632,647
Other Debt And Other Equity Securities | Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 1
Assets, Fair Value Disclosure [Abstract]
Equity securities with readily determinable fair values, Fair Value	6,286	5,991
Residential loans held for sale | Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 2
Assets, Fair Value Disclosure [Abstract]
Trading assets	35,742	20,383
Mortgage banking(a) | Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 3
Assets, Fair Value Disclosure [Abstract]
Trading assets	338	$ 86
Forward Commitments to Sell Residential Mortgage Loans | Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 3
Liabilities, Fair Value Disclosure [Abstract]
Trading liabilities	$ 441