Investment Securities - Contractual Maturities of Securities Available-for-Sale (Details) $ in Thousands	Jun. 30, 2022 USD ($)
Schedule of Investments [Line Items]
Contractual Maturities of Securities Available-for-Sale, Amortized Cost, Due Within One Year	$ 35,355
Contractual Maturities of Securities Available-for-Sale, Amortized Cost, Due After One Year Through Five Years	651,810
Contractual Maturities of Securities Available-for-Sale, Amortized Cost, Due After Five Years Through Ten Years	2,293,278
Contractual Maturities of Securities Available-for-Sale, Amortized Cost, Due After Ten Years	4,390,558
Total	7,371,001
Contractual Maturities of Securities Available-for-Sale, Fair Value, Due Within One Year	35,181
Contractual Maturities of Securities Available-for-Sale, Fair Value, Due Within One Year Through Five Years	638,020
Contractual Maturities of Securities Available-for-Sale, Fair Value, Due After Five Years Through Ten Years	2,112,173
Contractual Maturities of Securities Available-for-Sale, Fair Value, Due After Ten Years	(3,995,274)
Total	6,780,648
Agency residential MBS
Schedule of Investments [Line Items]
Contractual Maturities of Securities Available-for-Sale, Amortized Cost, Due Within One Year	28
Contractual Maturities of Securities Available-for-Sale, Amortized Cost, Due After One Year Through Five Years	6,756
Contractual Maturities of Securities Available-for-Sale, Amortized Cost, Due After Five Years Through Ten Years	4,625
Contractual Maturities of Securities Available-for-Sale, Amortized Cost, Due After Ten Years	2,887,075
Total	2,898,484
Contractual Maturities of Securities Available-for-Sale, Fair Value, Due Within One Year	29
Contractual Maturities of Securities Available-for-Sale, Fair Value, Due Within One Year Through Five Years	6,794
Contractual Maturities of Securities Available-for-Sale, Fair Value, Due After Five Years Through Ten Years	4,692
Contractual Maturities of Securities Available-for-Sale, Fair Value, Due After Ten Years	(2,566,200)
Total	2,577,715
Agency commercial MBS
Schedule of Investments [Line Items]
Contractual Maturities of Securities Available-for-Sale, Amortized Cost, Due Within One Year	6,847
Contractual Maturities of Securities Available-for-Sale, Amortized Cost, Due After One Year Through Five Years	529,921
Contractual Maturities of Securities Available-for-Sale, Amortized Cost, Due After Five Years Through Ten Years	452,921
Contractual Maturities of Securities Available-for-Sale, Amortized Cost, Due After Ten Years	30,394
Total	1,020,083
Contractual Maturities of Securities Available-for-Sale, Fair Value, Due Within One Year	6,847
Contractual Maturities of Securities Available-for-Sale, Fair Value, Due Within One Year Through Five Years	517,077
Contractual Maturities of Securities Available-for-Sale, Fair Value, Due After Five Years Through Ten Years	422,320
Contractual Maturities of Securities Available-for-Sale, Fair Value, Due After Ten Years	(29,977)
Total	976,221
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	1,487
Contractual Maturities of Securities Available-for-Sale, Amortized Cost, Due After Five Years Through Ten Years	206,723
Contractual Maturities of Securities Available-for-Sale, Amortized Cost, Due After Ten Years	636,298
Total	844,508
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	1,486
Contractual Maturities of Securities Available-for-Sale, Fair Value, Due After Five Years Through Ten Years	191,837
Contractual Maturities of Securities Available-for-Sale, Fair Value, Due After Ten Years	(609,986)
Total	803,309
Municipal securities
Schedule of Investments [Line Items]
Contractual Maturities of Securities Available-for-Sale, Amortized Cost, Due Within One Year	17,625
Contractual Maturities of Securities Available-for-Sale, Amortized Cost, Due After One Year Through Five Years	85,139
Contractual Maturities of Securities Available-for-Sale, Amortized Cost, Due After Five Years Through Ten Years	394,484
Contractual Maturities of Securities Available-for-Sale, Amortized Cost, Due After Ten Years	245,597
Total	742,845
Contractual Maturities of Securities Available-for-Sale, Fair Value, Due Within One Year	17,639
Contractual Maturities of Securities Available-for-Sale, Fair Value, Due Within One Year Through Five Years	84,751
Contractual Maturities of Securities Available-for-Sale, Fair Value, Due After Five Years Through Ten Years	355,007
Contractual Maturities of Securities Available-for-Sale, Fair Value, Due After Ten Years	(243,208)
Total	700,605
U.S. Treasury securities
Schedule of Investments [Line Items]
Contractual Maturities of Securities Available-for-Sale, Amortized Cost, Due Within One Year	4,996
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	766,023
Contractual Maturities of Securities Available-for-Sale, Amortized Cost, Due After Ten Years	0
Total	771,019
Contractual Maturities of Securities Available-for-Sale, Fair Value, Due Within One Year	4,995
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	691,059
Contractual Maturities of Securities Available-for-Sale, Fair Value, Due After Ten Years	0
Total	696,054
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	22,500
Contractual Maturities of Securities Available-for-Sale, Amortized Cost, Due After Five Years Through Ten Years	365,966
Contractual Maturities of Securities Available-for-Sale, Amortized Cost, Due After Ten Years	0
Total	388,466
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	22,050
Contractual Maturities of Securities Available-for-Sale, Fair Value, Due After Five Years Through Ten Years	347,411
Contractual Maturities of Securities Available-for-Sale, Fair Value, Due After Ten Years	0
Total	369,461
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	101,154
Contractual Maturities of Securities Available-for-Sale, Amortized Cost, Due After Ten Years	264,200
Total	365,354
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	98,461
Contractual Maturities of Securities Available-for-Sale, Fair Value, Due After Ten Years	(253,829)
Total	352,290
Private label 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	0
Contractual Maturities of Securities Available-for-Sale, Amortized Cost, Due After Ten Years	248,155
Total	248,155
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	(216,103)
Total	216,103
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	1,382
Contractual Maturities of Securities Available-for-Sale, Amortized Cost, Due After Ten Years	31,972
Total	33,354
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	1,386
Contractual Maturities of Securities Available-for-Sale, Fair Value, Due After Ten Years	(31,261)
Total	32,647
Private label commercial MBS
Schedule of Investments [Line Items]
Contractual Maturities of Securities Available-for-Sale, Amortized Cost, Due Within One Year	4,004
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	30,407
Total	34,411
Contractual Maturities of Securities Available-for-Sale, Fair Value, Due Within One Year	3,890
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	(28,626)
Total	32,516
SBA securities
Schedule of Investments [Line Items]
Contractual Maturities of Securities Available-for-Sale, Amortized Cost, Due Within One Year	1,855
Contractual Maturities of Securities Available-for-Sale, Amortized Cost, Due After One Year Through Five Years	6,007
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	16,460
Total	24,322
Contractual Maturities of Securities Available-for-Sale, Fair Value, Due Within One Year	1,781
Contractual Maturities of Securities Available-for-Sale, Fair Value, Due Within One Year Through Five Years	5,862
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	(16,084)
Total	$ 23,727

Amortized cost of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), with single maturity date and allocated without single maturity date, maturing in sixth through tenth fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

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