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Securities, Held to Maturity (Details) - USD ($) $ in Thousands | 3 Months Ended |
--- | --- | ---
Mar. 31, 2022 | Mar. 31, 2021 | Dec. 31, 2021
Held-to-maturity securities, fair value to amortized cost [Abstract] |  |  |
Amortized cost | $ 895,005 |  | $ 733,210
Unrealized gains | 762 |  | 10,040
Unrealized losses | 44,132 |  | 7,990
Estimated fair value | 851,635 |  | 735,260
Allowance for credit losses on HTM securities | 0 |  | 0
Transactions of HTM securities [Abstract] |  |  |
Gains from calls on HTM securities | 4 | $ 15 |
Asset Pledged as Collateral [Member] | Public Deposits or Other Purposes [Member] |  |  |
Securities pledged [Abstract] |  |  |
AFS and HTM securities | 1,800,000 |  | 1,600,000
Asset Pledged as Collateral [Member] | Securities Sold under Repurchase Agreements [Member] |  |  |
Securities pledged [Abstract] |  |  |
AFS and HTM securities | 144,900 |  | 162,100
Federal Agency [Member] |  |  |
Held-to-maturity securities, fair value to amortized cost [Abstract] |  |  |
Amortized cost | 100,000 |  | 100,000
Unrealized gains | 0 |  | 0
Unrealized losses | 10,872 |  | 4,365
Estimated fair value | 89,128 |  | 95,635
Mortgage-Backed, Government Sponsored Enterprises [Member] |  |  |
Held-to-maturity securities, fair value to amortized cost [Abstract] |  |  |
Amortized cost | 269,153 |  | 161,462
Unrealized gains | 137 |  | 2,232
Unrealized losses | 16,499 |  | 1,319
Estimated fair value | 252,791 |  | 162,375
Mortgage-Backed, U.S. Government Agency Securities [Member] |  |  |
Held-to-maturity securities, fair value to amortized cost [Abstract] |  |  |
Amortized cost | 7,425 |  | 9,112
Unrealized gains | 50 |  | 514
Unrealized losses | 6 |  | 0
Estimated fair value | 7,469 |  | 9,626
Collateralized Mortgage Obligations, Government-Sponsored Enterprises [Member] |  |  |
Held-to-maturity securities, fair value to amortized cost [Abstract] |  |  |
Amortized cost | 111,254 |  | 94,342
Unrealized gains | 105 |  | 1,932
Unrealized losses | 2,722 |  | 129
Estimated fair value | 108,637 |  | 96,145
Collateralized Mortgage Obligations, U.S. Government Agency Securities [Member] |  |  |
Held-to-maturity securities, fair value to amortized cost [Abstract] |  |  |
Amortized cost | 74,596 |  | 44,473
Unrealized gains | 76 |  | 336
Unrealized losses | 3,755 |  | 674
Estimated fair value | 70,917 |  | 44,135
State & Municipal [Member] |  |  |
Held-to-maturity securities, fair value to amortized cost [Abstract] |  |  |
Amortized cost | 332,577 |  | 323,821
Unrealized gains | 394 |  | 5,026
Unrealized losses | 10,278 |  | 1,503
Estimated fair value | $ 322,693 |  | $ 327,344

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