Securities - Scheduled Contractual Maturities of HTM Debt Securities (Details) $ in Thousands	Jun. 30, 2025 USD ($)
Amortized cost
Within One Year	$ 0
After One Year through Five Years	580,234
After Five Years through Ten Years	558,437
After Ten Years	1,754,311
Total	2,892,982
Fair value
Within One Year	0
After One Year through Five Years	553,495
After Five Years through Ten Years	486,735
After Ten Years	1,397,017
Total	$ 2,437,247
Weighted Average Yield
Within One Year	0.00%
After One Year through Five Years	1.08%
After Five Years through Ten Years	1.84%
After Ten Years	1.79%
Total	1.66%
U.S. Treasury securities
Amortized cost
Within One Year	$ 0
After One Year through Five Years	537,851
After Five Years through Ten Years	0
After Ten Years	0
Total	537,851
Fair value
Within One Year	0
After One Year through Five Years	514,767
After Five Years through Ten Years	0
After Ten Years	0
Total	$ 514,767
Weighted Average Yield
Within One Year	0.00%
After One Year through Five Years	1.05%
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	24,365
After Five Years through Ten Years	395,486
After Ten Years	585,887
Total	1,005,738
Fair value
Within One Year	0
After One Year through Five Years	22,057
After Five Years through Ten Years	346,789
After Ten Years	469,376
Total	$ 838,222
Weighted Average Yield
Within One Year	0.00%
After One Year through Five Years	1.42%
After Five Years through Ten Years	1.90%
After Ten Years	1.91%
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	18,018
After Five Years through Ten Years	162,951
After Ten Years	981,655
Total	1,162,624
Fair value
Within One Year	0
After One Year through Five Years	16,671
After Five Years through Ten Years	139,946
After Ten Years	788,064
Total	$ 944,681
Weighted Average Yield
Within One Year	0.00%
After One Year through Five Years	1.61%
After Five Years through Ten Years	1.69%
After Ten Years	1.68%
Total	1.68%
Municipal securities
Amortized cost
Within One Year	$ 0
After One Year through Five Years	0
After Five Years through Ten Years	0
After Ten Years	186,769
Total	186,769
Fair value
Within One Year	0
After One Year through Five Years	0
After Five Years through Ten Years	0
After Ten Years	139,577
Total	$ 139,577
Weighted Average Yield
Within One Year	0.00%
After One Year through Five Years	0.00%
After Five Years through Ten Years	0.00%
After Ten Years	2.02%
Total	2.02%