Investment Securities - Contractual Maturities of Securities Available-for-Sale (Details) $ in Thousands	Dec. 31, 2022 USD ($)
Investment Securities, Available-for-Sale, Amortized Cost
Due in one year or less	$ 12,923
Due after one year through five years	257,031
Due after five years through ten years	2,006,912
Due after ten years	3,377,751
Total	5,654,617
Investment Securities, Available-for-Sale, Estimated Fair Value
Due in one year or less	12,617
Due after one year through five years	235,295
Due after five years through ten years	1,749,230
Due after ten years	2,846,345
Total	4,843,487
Residential Mortgage Backed Securities [Member]
Investment Securities, Available-for-Sale, Amortized Cost
Due in one year or less	0
Due after one year through five years	0
Due after five years through ten years	0
Due after ten years	2,685,038
Total	2,685,038
Investment Securities, Available-for-Sale, Estimated Fair Value
Due in one year or less	0
Due after one year through five years	0
Due after five years through ten years	0
Due after ten years	2,242,042
Total	2,242,042
US Treasury Securities [Member]
Investment Securities, Available-for-Sale, Amortized Cost
Due in one year or less	4,998
Due after one year through five years	0
Due after five years through ten years	766,147
Due after ten years	0
Total	771,145
Investment Securities, Available-for-Sale, Estimated Fair Value
Due in one year or less	4,972
Due after one year through five years	0
Due after five years through ten years	665,098
Due after ten years	0
Total	670,070
Commercial Mortgage Backed Securities [Member]
Investment Securities, Available-for-Sale, Amortized Cost
Due in one year or less	0
Due after one year through five years	208,626
Due after five years through ten years	322,213
Due after ten years	18,653
Total	549,492
Investment Securities, Available-for-Sale, Estimated Fair Value
Due in one year or less	0
Due after one year through five years	192,142
Due after five years through ten years	277,940
Due after ten years	17,524
Total	487,606
Government agency and government-sponsored enterprise collateralized mortgage obligations [Member]
Investment Securities, Available-for-Sale, Amortized Cost
Due in one year or less	0
Due after one year through five years	0
Due after five years through ten years	178,348
Due after ten years	338,826
Total	517,174
Investment Securities, Available-for-Sale, Estimated Fair Value
Due in one year or less	0
Due after one year through five years	0
Due after five years through ten years	155,835
Due after ten years	301,228
Total	457,063
US States and Political Subdivisions Debt Securities [Member]
Investment Securities, Available-for-Sale, Amortized Cost
Due in one year or less	3,680
Due after one year through five years	43,405
Due after five years through ten years	330,116
Due after ten years	22,523
Total	399,724
Investment Securities, Available-for-Sale, Estimated Fair Value
Due in one year or less	3,680
Due after one year through five years	38,147
Due after five years through ten years	276,878
Due after ten years	20,621
Total	339,326
Corporate Debt Securities [Member]
Investment Securities, Available-for-Sale, Amortized Cost
Due in one year or less	0
Due after one year through five years	5,000
Due after five years through ten years	339,767
Due after ten years	0
Total	344,767
Investment Securities, Available-for-Sale, Estimated Fair Value
Due in one year or less	0
Due after one year through five years	5,006
Due after five years through ten years	306,899
Due after ten years	0
Total	311,905
Private Label Collateralized Mortgage Obligations [Member]
Investment Securities, Available-for-Sale, Amortized Cost
Due in one year or less	0
Due after one year through five years	0
Due after five years through ten years	0
Due after ten years	207,123
Total	207,123
Investment Securities, Available-for-Sale, Estimated Fair Value
Due in one year or less	0
Due after one year through five years	0
Due after five years through ten years	0
Due after ten years	166,724
Total	166,724
Collateralized Loan Obligations [Member]
Investment Securities, Available-for-Sale, Amortized Cost
Due in one year or less	0
Due after one year through five years	0
Due after five years through ten years	70,321
Due after ten years	38,838
Total	109,159
Investment Securities, Available-for-Sale, Estimated Fair Value
Due in one year or less	0
Due after one year through five years	0
Due after five years through ten years	66,580
Due after ten years	35,681
Total	102,261
Mortgage-backed Securities, Issued by Private Enterprises
Investment Securities, Available-for-Sale, Amortized Cost
Due in one year or less	0
Due after one year through five years	0
Due after five years through ten years	0
Due after ten years	28,903
Total	28,903
Investment Securities, Available-for-Sale, Estimated Fair Value
Due in one year or less	0
Due after one year through five years	0
Due after five years through ten years	0
Due after ten years	26,827
Total	26,827
Asset-backed Securities [Member]
Investment Securities, Available-for-Sale, Amortized Cost
Due in one year or less	0
Due after one year through five years	0
Due after five years through ten years	0
Due after ten years	23,568
Total	23,568
Investment Securities, Available-for-Sale, Estimated Fair Value
Due in one year or less	0
Due after one year through five years	0
Due after five years through ten years	0
Due after ten years	22,413
Total	22,413
SBA asset-backed securities [Member]
Investment Securities, Available-for-Sale, Amortized Cost
Due in one year or less	4,245
Due after one year through five years	0
Due after five years through ten years	0
Due after ten years	14,279
Total	18,524
Investment Securities, Available-for-Sale, Estimated Fair Value
Due in one year or less	3,965
Due after one year through five years	0
Due after five years through ten years	0
Due after ten years	13,285
Total	$ 17,250