Investment Securities - Contractual Maturities of Securities Available-for-Sale (Details) $ in Thousands	Mar. 31, 2023 USD ($)
Schedule of Investments [Line Items]
Contractual Maturities of Securities Available-for-Sale, Amortized Cost, Due Within One Year	$ 4,999
Contractual Maturities of Securities Available-for-Sale, Amortized Cost, Due After One Year Through Five Years	771,575
Contractual Maturities of Securities Available-for-Sale, Amortized Cost, Due After Five Years Through Ten Years	1,488,854
Contractual Maturities of Securities Available-for-Sale, Amortized Cost, Due After Ten Years	3,326,338
Contractual Maturities of Securities Available-for-Sale, Fair Value, Due Within One Year	4,993
Contractual Maturities of Securities Available-for-Sale, Fair Value, Due Within One Year Through Five Years	696,326
Contractual Maturities of Securities Available-for-Sale, Fair Value, Due After Five Years Through Ten Years	1,297,733
Contractual Maturities of Securities Available-for-Sale, Fair Value, Due After Ten Years	(2,849,555)
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, Amortized Cost	5,591,766
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, Fair Value	4,848,607
Agency residential MBS
Schedule of Investments [Line Items]
Contractual Maturities of Securities Available-for-Sale, Amortized Cost, Due Within One Year	0
Contractual Maturities of Securities Available-for-Sale, Amortized Cost, Due After One Year Through Five Years	0
Contractual Maturities of Securities Available-for-Sale, Amortized Cost, Due After Five Years Through Ten Years	0
Contractual Maturities of Securities Available-for-Sale, Amortized Cost, Due After Ten Years	2,645,975
Contractual Maturities of Securities Available-for-Sale, Fair Value, Due Within One Year	0
Contractual Maturities of Securities Available-for-Sale, Fair Value, Due Within One Year Through Five Years	0
Contractual Maturities of Securities Available-for-Sale, Fair Value, Due After Five Years Through Ten Years	0
Contractual Maturities of Securities Available-for-Sale, Fair Value, Due After Ten Years	(2,249,080)
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, Amortized Cost	2,645,975
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, Fair Value	2,249,080
Agency commercial MBS
Schedule of Investments [Line Items]
Contractual Maturities of Securities Available-for-Sale, Amortized Cost, Due Within One Year	0
Contractual Maturities of Securities Available-for-Sale, Amortized Cost, Due After One Year Through Five Years	205,442
Contractual Maturities of Securities Available-for-Sale, Amortized Cost, Due After Five Years Through Ten Years	321,502
Contractual Maturities of Securities Available-for-Sale, Amortized Cost, Due After Ten Years	18,536
Contractual Maturities of Securities Available-for-Sale, Fair Value, Due Within One Year	0
Contractual Maturities of Securities Available-for-Sale, Fair Value, Due Within One Year Through Five Years	191,319
Contractual Maturities of Securities Available-for-Sale, Fair Value, Due After Five Years Through Ten Years	282,520
Contractual Maturities of Securities Available-for-Sale, Fair Value, Due After Ten Years	(17,842)
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, Amortized Cost	545,480
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, Fair Value	491,681
Agency residential CMOs
Schedule of Investments [Line Items]
Contractual Maturities of Securities Available-for-Sale, Amortized Cost, Due Within One Year	0
Contractual Maturities of Securities Available-for-Sale, Amortized Cost, Due After One Year Through Five Years	0
Contractual Maturities of Securities Available-for-Sale, Amortized Cost, Due After Five Years Through Ten Years	175,473
Contractual Maturities of Securities Available-for-Sale, Amortized Cost, Due After Ten Years	333,830
Contractual Maturities of Securities Available-for-Sale, Fair Value, Due Within One Year	0
Contractual Maturities of Securities Available-for-Sale, Fair Value, Due Within One Year Through Five Years	0
Contractual Maturities of Securities Available-for-Sale, Fair Value, Due After Five Years Through Ten Years	154,603
Contractual Maturities of Securities Available-for-Sale, Fair Value, Due After Ten Years	(301,079)
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, Amortized Cost	509,303
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, Fair Value	455,682
Municipal securities
Schedule of Investments [Line Items]
Contractual Maturities of Securities Available-for-Sale, Amortized Cost, Due Within One Year	0
Contractual Maturities of Securities Available-for-Sale, Amortized Cost, Due After One Year Through Five Years	53,855
Contractual Maturities of Securities Available-for-Sale, Amortized Cost, Due After Five Years Through Ten Years	319,463
Contractual Maturities of Securities Available-for-Sale, Amortized Cost, Due After Ten Years	22,391
Contractual Maturities of Securities Available-for-Sale, Fair Value, Due Within One Year	0
Contractual Maturities of Securities Available-for-Sale, Fair Value, Due Within One Year Through Five Years	48,293
Contractual Maturities of Securities Available-for-Sale, Fair Value, Due After Five Years Through Ten Years	276,487
Contractual Maturities of Securities Available-for-Sale, Fair Value, Due After Ten Years	(20,859)
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, Amortized Cost	395,709
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, Fair Value	345,639
U.S. Treasury securities
Schedule of Investments [Line Items]
Contractual Maturities of Securities Available-for-Sale, Amortized Cost, Due Within One Year	4,999
Contractual Maturities of Securities Available-for-Sale, Amortized Cost, Due After One Year Through Five Years	503,869
Contractual Maturities of Securities Available-for-Sale, Amortized Cost, Due After Five Years Through Ten Years	262,340
Contractual Maturities of Securities Available-for-Sale, Amortized Cost, Due After Ten Years	0
Contractual Maturities of Securities Available-for-Sale, Fair Value, Due Within One Year	4,993
Contractual Maturities of Securities Available-for-Sale, Fair Value, Due Within One Year Through Five Years	448,478
Contractual Maturities of Securities Available-for-Sale, Fair Value, Due After Five Years Through Ten Years	231,965
Contractual Maturities of Securities Available-for-Sale, Fair Value, Due After Ten Years	0
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, Amortized Cost	771,208
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, Fair Value	685,436
Corporate Debt Securities
Schedule of Investments [Line Items]
Contractual Maturities of Securities Available-for-Sale, Amortized Cost, Due Within One Year	0
Contractual Maturities of Securities Available-for-Sale, Amortized Cost, Due After One Year Through Five Years	5,000
Contractual Maturities of Securities Available-for-Sale, Amortized Cost, Due After Five Years Through Ten Years	339,747
Contractual Maturities of Securities Available-for-Sale, Amortized Cost, Due After Ten Years	0
Contractual Maturities of Securities Available-for-Sale, Fair Value, Due Within One Year	0
Contractual Maturities of Securities Available-for-Sale, Fair Value, Due Within One Year Through Five Years	4,957
Contractual Maturities of Securities Available-for-Sale, Fair Value, Due After Five Years Through Ten Years	284,837
Contractual Maturities of Securities Available-for-Sale, Fair Value, Due After Ten Years	0
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, Amortized Cost	344,747
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, Fair Value	289,794
Collateralized loan obligations
Schedule of Investments [Line Items]
Contractual Maturities of Securities Available-for-Sale, Amortized Cost, Due Within One Year	0
Contractual Maturities of Securities Available-for-Sale, Amortized Cost, Due After One Year Through Five Years	0
Contractual Maturities of Securities Available-for-Sale, Amortized Cost, Due After Five Years Through Ten Years	70,329
Contractual Maturities of Securities Available-for-Sale, Amortized Cost, Due After Ten Years	38,837
Contractual Maturities of Securities Available-for-Sale, Fair Value, Due Within One Year	0
Contractual Maturities of Securities Available-for-Sale, Fair Value, Due Within One Year Through Five Years	0
Contractual Maturities of Securities Available-for-Sale, Fair Value, Due After Five Years Through Ten Years	67,321
Contractual Maturities of Securities Available-for-Sale, Fair Value, Due After Ten Years	(35,673)
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, Amortized Cost	109,166
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, Fair Value	102,994
Private label commercial MBS
Schedule of Investments [Line Items]
Contractual Maturities of Securities Available-for-Sale, Amortized Cost, Due Within One Year	0
Contractual Maturities of Securities Available-for-Sale, Amortized Cost, Due After One Year Through Five Years	0
Contractual Maturities of Securities Available-for-Sale, Amortized Cost, Due After Five Years Through Ten Years	0
Contractual Maturities of Securities Available-for-Sale, Amortized Cost, Due After Ten Years	27,331
Contractual Maturities of Securities Available-for-Sale, Fair Value, Due Within One Year	0
Contractual Maturities of Securities Available-for-Sale, Fair Value, Due Within One Year Through Five Years	0
Contractual Maturities of Securities Available-for-Sale, Fair Value, Due After Five Years Through Ten Years	0
Contractual Maturities of Securities Available-for-Sale, Fair Value, Due After Ten Years	(25,535)
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, Amortized Cost	27,331
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, Fair Value	25,535
SBA securities
Schedule of Investments [Line Items]
Contractual Maturities of Securities Available-for-Sale, Amortized Cost, Due Within One Year	0
Contractual Maturities of Securities Available-for-Sale, Amortized Cost, Due After One Year Through Five Years	3,409
Contractual Maturities of Securities Available-for-Sale, Amortized Cost, Due After Five Years Through Ten Years	0
Contractual Maturities of Securities Available-for-Sale, Amortized Cost, Due After Ten Years	13,486
Contractual Maturities of Securities Available-for-Sale, Fair Value, Due Within One Year	0
Contractual Maturities of Securities Available-for-Sale, Fair Value, Due Within One Year Through Five Years	3,279
Contractual Maturities of Securities Available-for-Sale, Fair Value, Due After Five Years Through Ten Years	0
Contractual Maturities of Securities Available-for-Sale, Fair Value, Due After Ten Years	(12,627)
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, Amortized Cost	16,895
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, Fair Value	15,906
Private Label Collateralized Mortgage Obligations
Schedule of Investments [Line Items]
Contractual Maturities of Securities Available-for-Sale, Amortized Cost, Due Within One Year	0
Contractual Maturities of Securities Available-for-Sale, Amortized Cost, Due After One Year Through Five Years	0
Contractual Maturities of Securities Available-for-Sale, Amortized Cost, Due After Five Years Through Ten Years	0
Contractual Maturities of Securities Available-for-Sale, Amortized Cost, Due After Ten Years	203,088
Contractual Maturities of Securities Available-for-Sale, Fair Value, Due Within One Year	0
Contractual Maturities of Securities Available-for-Sale, Fair Value, Due Within One Year Through Five Years	0
Contractual Maturities of Securities Available-for-Sale, Fair Value, Due After Five Years Through Ten Years	0
Contractual Maturities of Securities Available-for-Sale, Fair Value, Due After Ten Years	(164,403)
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, Amortized Cost	203,088
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, Fair Value	164,403
Asset-backed Securities
Schedule of Investments [Line Items]
Contractual Maturities of Securities Available-for-Sale, Amortized Cost, Due Within One Year	0
Contractual Maturities of Securities Available-for-Sale, Amortized Cost, Due After One Year Through Five Years	0
Contractual Maturities of Securities Available-for-Sale, Amortized Cost, Due After Five Years Through Ten Years	0
Contractual Maturities of Securities Available-for-Sale, Amortized Cost, Due After Ten Years	22,864
Contractual Maturities of Securities Available-for-Sale, Fair Value, Due Within One Year	0
Contractual Maturities of Securities Available-for-Sale, Fair Value, Due Within One Year Through Five Years	0
Contractual Maturities of Securities Available-for-Sale, Fair Value, Due After Five Years Through Ten Years	0
Contractual Maturities of Securities Available-for-Sale, Fair Value, Due After Ten Years	(22,457)
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, Amortized Cost	22,864
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, Fair Value	$ 22,457