Securities - Gross Unrealized Losses and Fair Value by Investment Category (Details) $ in Thousands	Sep. 30, 2022 USD ($) security	Dec. 31, 2021 USD ($) security
Available for Sale:
Number of positions, Less than 12 Months | security	286	121
Fair Value, Less than 12 Months	$ 1,004,652	$ 1,899,384
Unrealized Losses, Less than 12 Months	$ (98,363)	$ (30,120)
Number of positions, 12 Months or More | security	68	7
Fair value, 12 Months or More	$ 553,775	$ 25,634
Unrealized Losses, 12 Months or More	$ (113,413)	$ (904)
Number of positions | security	354	128
Fair Value	$ 1,558,427	$ 1,925,018
Unrealized Losses	$ (211,776)	$ (31,024)
Held to Maturity:
Number of positions, Less than 12 Months | security	196	90
Fair Value, Less than 12 Months	$ 777,985	$ 201,791
Unrealized Losses, Less than 12 Months	$ (95,338)	$ (1,154)
Number of positions, 12 Months or More | security	43	1
Fair Value, 12 Months or More	$ 440,671	$ 5,354
Unrealized Losses, 12 Months or More	$ (39,540)	$ (17)
Number of positions | security	239	91
Fair Value	$ 1,218,656	$ 207,145
Unrealized Losses	$ (134,878)	$ (1,171)
Obligations of other U.S. Government agencies and corporations
Available for Sale:
Number of positions, Less than 12 Months | security	5
Fair Value, Less than 12 Months	$ 164,520
Unrealized Losses, Less than 12 Months	$ (5,480)
Number of positions, 12 Months or More | security	0
Fair value, 12 Months or More	$ 0
Unrealized Losses, 12 Months or More	$ 0
Number of positions | security	5
Fair Value	$ 164,520
Unrealized Losses	$ (5,480)
Obligations of states and political subdivisions
Available for Sale:
Number of positions, Less than 12 Months | security	95	8
Fair Value, Less than 12 Months	$ 100,822	$ 34,303
Unrealized Losses, Less than 12 Months	$ (8,433)	$ (216)
Number of positions, 12 Months or More | security	11	3
Fair value, 12 Months or More	$ 31,571	$ 3,892
Unrealized Losses, 12 Months or More	$ (6,202)	$ (53)
Number of positions | security	106	11
Fair Value	$ 132,393	$ 38,195
Unrealized Losses	$ (14,635)	$ (269)
Held to Maturity:
Number of positions, Less than 12 Months | security	125	24
Fair Value, Less than 12 Months	$ 212,242	$ 62,131
Unrealized Losses, Less than 12 Months	$ (57,474)	$ (685)
Number of positions, 12 Months or More | security	5	0
Fair Value, 12 Months or More	$ 16,925	$ 0
Unrealized Losses, 12 Months or More	$ (6,128)	$ 0
Number of positions | security	130	24
Fair Value	$ 229,167	$ 62,131
Unrealized Losses	$ (63,602)	$ (685)
Trust preferred securities
Available for Sale:
Number of positions, Less than 12 Months | security		0
Fair Value, Less than 12 Months		$ 0
Unrealized Losses, Less than 12 Months		$ 0
Number of positions, 12 Months or More | security		0
Fair value, 12 Months or More		$ 0
Unrealized Losses, 12 Months or More		$ 0
Number of positions | security		0
Fair Value		$ 0
Unrealized Losses		$ 0
Other debt securities
Available for Sale:
Number of positions, Less than 12 Months | security	32	1
Fair Value, Less than 12 Months	$ 70,317	$ 8,699
Unrealized Losses, Less than 12 Months	$ (3,571)	$ (148)
Number of positions, 12 Months or More | security	0	0
Fair value, 12 Months or More	$ 0	$ 0
Unrealized Losses, 12 Months or More	$ 0	$ 0
Number of positions | security	32	1
Fair Value	$ 70,317	$ 8,699
Unrealized Losses	$ (3,571)	$ (148)
Held to Maturity:
Number of positions, Less than 12 Months | security	10	8
Fair Value, Less than 12 Months	$ 60,013	$ 21,972
Unrealized Losses, Less than 12 Months	$ (5,331)	$ (79)
Number of positions, 12 Months or More | security	0	0
Fair Value, 12 Months or More	$ 0	$ 0
Unrealized Losses, 12 Months or More	$ 0	$ 0
Number of positions | security	10	8
Fair Value	$ 60,013	$ 21,972
Unrealized Losses	$ (5,331)	$ (79)
Government agency mortgage backed securities | Residential mortgage backed securities:
Available for Sale:
Number of positions, Less than 12 Months | security	104	41
Fair Value, Less than 12 Months	$ 291,428	$ 727,546
Unrealized Losses, Less than 12 Months	$ (28,600)	$ (6,312)
Number of positions, 12 Months or More | security	22	1
Fair value, 12 Months or More	$ 176,036	$ 12,305
Unrealized Losses, 12 Months or More	$ (30,581)	$ (504)
Number of positions | security	126	42
Fair Value	$ 467,464	$ 739,851
Unrealized Losses	$ (59,181)	$ (6,816)
Held to Maturity:
Number of positions, Less than 12 Months | security	48	50
Fair Value, Less than 12 Months	$ 272,247	$ 53,560
Unrealized Losses, Less than 12 Months	$ (14,993)	$ (181)
Number of positions, 12 Months or More | security	23	1
Fair Value, 12 Months or More	$ 197,823	$ 5,354
Unrealized Losses, 12 Months or More	$ (14,285)	$ (17)
Number of positions | security	71	51
Fair Value	$ 470,070	$ 58,914
Unrealized Losses	$ (29,278)	$ (198)
Government agency mortgage backed securities | Commercial mortgage backed securities:
Available for Sale:
Number of positions, Less than 12 Months | security	4	1
Fair Value, Less than 12 Months	$ 10,247	$ 1,791
Unrealized Losses, Less than 12 Months	$ (957)	$ (1)
Number of positions, 12 Months or More | security	0	1
Fair value, 12 Months or More	$ 0	$ 432
Unrealized Losses, 12 Months or More	$ 0	$ 0
Number of positions | security	4	2
Fair Value	$ 10,247	$ 2,223
Unrealized Losses	$ (957)	$ (1)
Held to Maturity:
Number of positions, Less than 12 Months | security	1
Fair Value, Less than 12 Months	$ 13,582
Unrealized Losses, Less than 12 Months	$ (3,429)
Number of positions, 12 Months or More | security	0
Fair Value, 12 Months or More	$ 0
Unrealized Losses, 12 Months or More	$ 0
Number of positions | security	1
Fair Value	$ 13,582
Unrealized Losses	$ (3,429)
Government agency collateralized mortgage obligations | Residential mortgage backed securities:
Available for Sale:
Number of positions, Less than 12 Months | security	28	49
Fair Value, Less than 12 Months	$ 248,142	$ 966,126
Unrealized Losses, Less than 12 Months	$ (39,982)	$ (20,371)
Number of positions, 12 Months or More | security	24	0
Fair value, 12 Months or More	$ 275,856	$ 0
Unrealized Losses, 12 Months or More	$ (62,841)	$ 0
Number of positions | security	52	49
Fair Value	$ 523,998	$ 966,126
Unrealized Losses	$ (102,823)	$ (20,371)
Held to Maturity:
Number of positions, Less than 12 Months | security	9	1
Fair Value, Less than 12 Months	$ 206,711	$ 24,740
Unrealized Losses, Less than 12 Months	$ (12,589)	$ (92)
Number of positions, 12 Months or More | security	9	0
Fair Value, 12 Months or More	$ 199,658	$ 0
Unrealized Losses, 12 Months or More	$ (14,449)	$ 0
Number of positions | security	18	1
Fair Value	$ 406,369	$ 24,740
Unrealized Losses	$ (27,038)	$ (92)
Government agency collateralized mortgage obligations | Commercial mortgage backed securities:
Available for Sale:
Number of positions, Less than 12 Months | security	18	21
Fair Value, Less than 12 Months	$ 119,176	$ 160,919
Unrealized Losses, Less than 12 Months	$ (11,340)	$ (3,072)
Number of positions, 12 Months or More | security	11	2
Fair value, 12 Months or More	$ 70,312	$ 9,005
Unrealized Losses, 12 Months or More	$ (13,789)	$ (347)
Number of positions | security	29	23
Fair Value	$ 189,488	$ 169,924
Unrealized Losses	$ (25,129)	$ (3,419)
Held to Maturity:
Number of positions, Less than 12 Months | security	3	7
Fair Value, Less than 12 Months	$ 13,190	$ 39,388
Unrealized Losses, Less than 12 Months	$ (1,522)	$ (117)
Number of positions, 12 Months or More | security	6	0
Fair Value, 12 Months or More	$ 26,265	$ 0
Unrealized Losses, 12 Months or More	$ (4,678)	$ 0
Number of positions | security	9	7
Fair Value	$ 39,455	$ 39,388
Unrealized Losses	$ (6,200)	$ (117)