Securities - Investment Category and Length of Time in Unrealized Loss Position (Details) $ in Thousands	Dec. 31, 2021 USD ($) security	Dec. 31, 2020 USD ($) security
Available for Sale:
Number of positions, Less than 12 Months | security	121	21
Fair Value, Less than 12 Months	$ 1,899,384	$ 75,359
Unrealized Losses, Less than 12 Months	$ (30,120)	$ (211)
Number of positions, 12 Months or More | security	7	4
Fair Value, 12 Months or More	$ 25,634	$ 10,037
Unrealized Losses, 12 Months or More	$ (904)	$ (3,004)
Number of positions | security	128	25
Fair Value	$ 1,925,018	$ 85,396
Unrealized Losses	$ (31,024)	$ (3,215)
Held to Maturity:
Number of positions, Less than 12 Months | security	90,000
Fair Value, Less than 12 Months	$ 201,791
Unrealized Losses, Less than 12 Months	$ (1,154)
Number of positions, 12 Months or More | security	1,000
Fair Value, 12 Months or More	$ 5,354
Unrealized Losses, 12 Months or More	$ (17)
Number of positions | security	91,000
Fair Value	$ 207,145
Unrealized Losses	$ (1,171)
Obligations of states and political subdivisions
Available for Sale:
Number of positions, Less than 12 Months | security	8	6
Fair Value, Less than 12 Months	$ 34,303	$ 9,403
Unrealized Losses, Less than 12 Months	$ (216)	$ (45)
Number of positions, 12 Months or More | security	3	0
Fair Value, 12 Months or More	$ 3,892	$ 0
Unrealized Losses, 12 Months or More	$ (53)	$ 0
Number of positions | security	11	6
Fair Value	$ 38,195	$ 9,403
Unrealized Losses	$ (269)	$ (45)
Held to Maturity:
Number of positions, Less than 12 Months | security	24,000
Fair Value, Less than 12 Months	$ 62,131
Unrealized Losses, Less than 12 Months	$ (685)
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	24,000
Fair Value	$ 62,131
Unrealized Losses	$ (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		2
Fair Value, 12 Months or More		$ 9,012
Unrealized Losses, 12 Months or More		$ (3,001)
Number of positions | security		2
Fair Value		$ 9,012
Unrealized Losses		$ (3,001)
Other debt securities
Available for Sale:
Number of positions, Less than 12 Months | security	1	4
Fair Value, Less than 12 Months	$ 8,699	$ 3,330
Unrealized Losses, Less than 12 Months	$ (148)	$ (70)
Number of positions, 12 Months or More | security	0	1
Fair Value, 12 Months or More	$ 0	$ 566
Unrealized Losses, 12 Months or More	$ 0	$ (3)
Number of positions | security	1	5
Fair Value	$ 8,699	$ 3,896
Unrealized Losses	$ (148)	$ (73)
Held to Maturity:
Number of positions, Less than 12 Months | security	8,000
Fair Value, Less than 12 Months	$ 21,972
Unrealized Losses, Less than 12 Months	$ (79)
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	8,000
Fair Value	$ 21,972
Unrealized Losses	$ (79)
Government agency mortgage backed securities | Residential mortgage backed securities:
Available for Sale:
Number of positions, Less than 12 Months | security	41	2
Fair Value, Less than 12 Months	$ 727,546	$ 19,755
Unrealized Losses, Less than 12 Months	$ (6,312)	$ (23)
Number of positions, 12 Months or More | security	1	0
Fair Value, 12 Months or More	$ 12,305	$ 0
Unrealized Losses, 12 Months or More	$ (504)	$ 0
Number of positions | security	42	2
Fair Value	$ 739,851	$ 19,755
Unrealized Losses	$ (6,816)	$ (23)
Held to Maturity:
Number of positions, Less than 12 Months | security	50,000
Fair Value, Less than 12 Months	$ 53,560
Unrealized Losses, Less than 12 Months	$ (181)
Number of positions, 12 Months or More | security	1,000
Fair Value, 12 Months or More	$ 5,354
Unrealized Losses, 12 Months or More	$ (17)
Number of positions | security	51,000
Fair Value	$ 58,914
Unrealized Losses	$ (198)
Government agency mortgage backed securities | Commercial mortgage backed securities:
Available for Sale:
Number of positions, Less than 12 Months | security	1	1
Fair Value, Less than 12 Months	$ 1,791	$ 1,538
Unrealized Losses, Less than 12 Months	$ (1)	$ (1)
Number of positions, 12 Months or More | security	1	1
Fair Value, 12 Months or More	$ 432	$ 459
Unrealized Losses, 12 Months or More	$ 0	$ 0
Number of positions | security	2	2
Fair Value	$ 2,223	$ 1,997
Unrealized Losses	$ (1)	$ (1)
Government agency collateralized mortgage obligations | Residential mortgage backed securities:
Available for Sale:
Number of positions, Less than 12 Months | security	49	5
Fair Value, Less than 12 Months	$ 966,126	$ 27,143
Unrealized Losses, Less than 12 Months	$ (20,371)	$ (51)
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	49	5
Fair Value	$ 966,126	$ 27,143
Unrealized Losses	$ (20,371)	$ (51)
Held to Maturity:
Number of positions, Less than 12 Months | security	1,000
Fair Value, Less than 12 Months	$ 24,740
Unrealized Losses, Less than 12 Months	$ (92)
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	1,000
Fair Value	$ 24,740
Unrealized Losses	$ (92)
Government agency collateralized mortgage obligations | Commercial mortgage backed securities:
Available for Sale:
Number of positions, Less than 12 Months | security	21	3
Fair Value, Less than 12 Months	$ 160,919	$ 14,190
Unrealized Losses, Less than 12 Months	$ (3,072)	$ (21)
Number of positions, 12 Months or More | security	2	0
Fair Value, 12 Months or More	$ 9,005	$ 0
Unrealized Losses, 12 Months or More	$ (347)	$ 0
Number of positions | security	23	3
Fair Value	$ 169,924	$ 14,190
Unrealized Losses	$ (3,419)	$ (21)
Held to Maturity:
Number of positions, Less than 12 Months | security	7,000
Fair Value, Less than 12 Months	$ 39,388
Unrealized Losses, Less than 12 Months	$ (117)
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	7,000
Fair Value	$ 39,388
Unrealized Losses	$ (117)