Securities - Amortized Cost and Fair Value of Securities (Details) - USD ($) $ in Thousands	6 Months Ended	12 Months Ended
	Jun. 30, 2022	Dec. 31, 2021
Securities available-for-sale [Abstract]
Amortized Cost	$ 4,052,896	$ 4,858,544
Gross Unrealized Gains	6,100	88,336
Gross Unrealized Losses	249,658	32,686
Fair Value	3,809,338	4,914,194
Available-for-sale, Amortized Cost [Abstract]
Due in one year or less	34,637
Due in one year to five years	169,777
Due in five years to ten years	374,434
Due after ten years	1,784,053
Mortgage-backed securities	1,524,170
Asset-backed securities	165,825
Amortized Cost	4,052,896	4,858,544
Available-for-sale, Fair Value [Abstract]
Due in one year or less	34,521
Due in one year to five years	171,874
Due in five years to ten years	359,517
Due after ten years	1,692,338
Mortgage-backed securities	1,397,678
Asset-backed securities	153,410
Fair Value	3,809,338	4,914,194
Securities held-to-maturity [Abstract]
Amortized Cost	2,745,763	1,156,119
Gross Unrealized Gains	306	33,052
Gross Unrealized Losses	261,711	1,122
Fair Value	2,484,358	1,188,049
Allowance for credit losses - securities held-to-maturity	(1,208)	(161)
HeldToMaturitySecurities, net of allowance for credit losses	2,744,555	1,155,958
Held-to-maturity, Amortized Cost [Abstract]
Due in one year or less	1,979
Due in one year to five years	317,795
Due in five years to ten years	112,841
Due after ten years	1,745,330
Mortgage-backed securities	404,608
Asset-backed securities	163,210
Amortized Cost	2,745,763	1,156,119
Held-to-maturity, Fair Value [Abstract]
Due in one year or less	1,965
Due in one year to five years	300,462
Due in five years to ten years	109,314
Due after ten years	1,546,982
Mortgage-backed securities	374,252
Asset-backed securities	151,383
Fair Value	2,484,358	1,188,049
U.S. Treasury securities
Securities available-for-sale [Abstract]
Amortized Cost	246,604	194,490
Gross Unrealized Gains	184	0
Gross Unrealized Losses	685	881
Fair Value	246,103	193,609
Available-for-sale, Amortized Cost [Abstract]
Amortized Cost	246,604	194,490
Available-for-sale, Fair Value [Abstract]
Fair Value	246,103	193,609
Securities held-to-maturity [Abstract]
Amortized Cost	92,938
Gross Unrealized Gains	0
Gross Unrealized Losses	4,748
Fair Value	88,190
Held-to-maturity, Amortized Cost [Abstract]
Amortized Cost	92,938
Held-to-maturity, Fair Value [Abstract]
Fair Value	88,190
U.S. Government agency securities
Securities available-for-sale [Abstract]
Amortized Cost	440,148	634,611
Gross Unrealized Gains	0	2,359
Gross Unrealized Losses	24,633	4,961
Fair Value	415,515	632,009
Available-for-sale, Amortized Cost [Abstract]
Amortized Cost	440,148	634,611
Available-for-sale, Fair Value [Abstract]
Fair Value	415,515	632,009
Securities held-to-maturity [Abstract]
Amortized Cost	328,982	11,920
Gross Unrealized Gains	0	0
Gross Unrealized Losses	16,433	37
Fair Value	312,549	11,883
Held-to-maturity, Amortized Cost [Abstract]
Amortized Cost	328,982	11,920
Held-to-maturity, Fair Value [Abstract]
Fair Value	312,549	11,883
Mortgage-backed securities
Securities available-for-sale [Abstract]
Amortized Cost	1,524,170	1,908,675
Gross Unrealized Gains	685	29,874
Gross Unrealized Losses	127,177	18,310
Fair Value	1,397,678	1,920,239
Available-for-sale, Amortized Cost [Abstract]
Amortized Cost	1,524,170	1,908,675
Available-for-sale, Fair Value [Abstract]
Fair Value	1,397,678	1,920,239
Securities held-to-maturity [Abstract]
Amortized Cost	404,608	106,555
Gross Unrealized Gains	0	86
Gross Unrealized Losses	30,356	196
Fair Value	374,252	106,445
Held-to-maturity, Amortized Cost [Abstract]
Amortized Cost	404,608	106,555
Held-to-maturity, Fair Value [Abstract]
Fair Value	374,252	106,445
State and municipal securities
Securities available-for-sale [Abstract]
Amortized Cost	1,558,987	1,774,119
Gross Unrealized Gains	4,741	52,961
Gross Unrealized Losses	78,341	3,243
Fair Value	1,485,387	1,823,837
Available-for-sale, Amortized Cost [Abstract]
Amortized Cost	1,558,987	1,774,119
Available-for-sale, Fair Value [Abstract]
Fair Value	1,485,387	1,823,837
Securities held-to-maturity [Abstract]
Amortized Cost	1,741,998	1,037,644
Gross Unrealized Gains	306	32,966
Gross Unrealized Losses	197,534	889
Fair Value	1,544,770	1,069,721
Held-to-maturity, Amortized Cost [Abstract]
Amortized Cost	1,741,998	1,037,644
Held-to-maturity, Fair Value [Abstract]
Fair Value	1,544,770	1,069,721
Asset-backed securities
Securities available-for-sale [Abstract]
Amortized Cost	165,825	232,294
Gross Unrealized Gains	0	60
Gross Unrealized Losses	12,415	2,785
Fair Value	153,410	229,569
Available-for-sale, Amortized Cost [Abstract]
Amortized Cost	165,825	232,294
Available-for-sale, Fair Value [Abstract]
Fair Value	153,410	229,569
Securities held-to-maturity [Abstract]
Amortized Cost	163,210
Gross Unrealized Gains	0
Gross Unrealized Losses	11,827
Fair Value	151,383
Held-to-maturity, Amortized Cost [Abstract]
Amortized Cost	163,210
Held-to-maturity, Fair Value [Abstract]
Fair Value	151,383
Corporate notes and other
Securities available-for-sale [Abstract]
Amortized Cost	117,162	114,355
Gross Unrealized Gains	490	3,082
Gross Unrealized Losses	6,407	2,506
Fair Value	111,245	114,931
Available-for-sale, Amortized Cost [Abstract]
Amortized Cost	117,162	114,355
Available-for-sale, Fair Value [Abstract]
Fair Value	111,245	$ 114,931
Securities held-to-maturity [Abstract]
Amortized Cost	14,027
Gross Unrealized Gains	0
Gross Unrealized Losses	813
Fair Value	13,214
Held-to-maturity, Amortized Cost [Abstract]
Amortized Cost	14,027
Held-to-maturity, Fair Value [Abstract]
Fair Value	$ 13,214