Securities - Scheduled Contractual Maturities of HTM Debt Securities (Details) $ in Thousands	Jun. 30, 2026 USD ($)
Amortized cost
Within One Year	$ 223,023
After One Year through Five Years	518,663
After Five Years through Ten Years	1,040,826
After Ten Years	1,062,852
Total	2,845,364
Fair value
Within One Year	218,507
After One Year through Five Years	490,589
After Five Years through Ten Years	876,592
After Ten Years	857,806
Total	$ 2,443,494
Weighted Average Yield
Within One Year	0.93%
After One Year through Five Years	1.25%
After Five Years through Ten Years	1.92%
After Ten Years	1.75%
Total	1.66%
U.S. Treasury securities
Amortized cost
Within One Year	$ 223,023
After One Year through Five Years	320,443
After Five Years through Ten Years	0
After Ten Years	0
Total	543,466
Fair value
Within One Year	218,507
After One Year through Five Years	309,928
After Five Years through Ten Years	0
After Ten Years	0
Total	$ 528,435
Weighted Average Yield
Within One Year	0.93%
After One Year through Five Years	1.13%
After Five Years through Ten Years	0.00%
After Ten Years	0.00%
Total	1.05%
U.S. government agency and U.S. government-sponsored enterprise debt securities
Amortized cost
Within One Year	$ 0
After One Year through Five Years	130,134
After Five Years through Ten Years	812,871
After Ten Years	65,308
Total	1,008,313
Fair value
Within One Year	0
After One Year through Five Years	118,579
After Five Years through Ten Years	682,053
After Ten Years	53,074
Total	$ 853,706
Weighted Average Yield
Within One Year	0.00%
After One Year through Five Years	1.37%
After Five Years through Ten Years	1.96%
After Ten Years	2.12%
Total	1.90%
U.S. government agency and U.S. government-sponsored enterprise mortgage-backed securities
Amortized cost
Within One Year	$ 0
After One Year through Five Years	68,086
After Five Years through Ten Years	214,143
After Ten Years	827,115
Total	1,109,344
Fair value
Within One Year	0
After One Year through Five Years	62,082
After Five Years through Ten Years	182,459
After Ten Years	668,230
Total	$ 912,771
Weighted Average Yield
Within One Year	0.00%
After One Year through Five Years	1.60%
After Five Years through Ten Years	1.72%
After Ten Years	1.67%
Total	1.68%
Municipal securities
Amortized cost
Within One Year	$ 0
After One Year through Five Years	0
After Five Years through Ten Years	13,812
After Ten Years	170,429
Total	184,241
Fair value
Within One Year	0
After One Year through Five Years	0
After Five Years through Ten Years	12,080
After Ten Years	136,502
Total	$ 148,582
Weighted Average Yield
Within One Year	0.00%
After One Year through Five Years	0.00%
After Five Years through Ten Years	2.35%
After Ten Years	1.99%
Total	2.02%