Fair Value of Assets and Liabilities - Schedule of Carrying Amount, Fair Value, and Fair Value Hierarchy of Financial Instruments (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Financial Instruments - Assets
Held-to-Maturity: Fair Value	$ 4,171,262	$ 4,646,619
Carrying Amount
Financial Instruments - Assets
Held-to-Maturity: Fair Value	4,489,615	4,694,780
Loans	12,224,018	11,921,869
Financial Instruments - Liabilities
Time Deposits	922,519	1,000,089
Securities Sold Under Agreements to Repurchase	450,490	450,490
Fair Value
Financial Instruments - Assets
Held-to-Maturity: Fair Value	4,171,262	4,646,619
Loans	11,931,447	12,094,631
Financial Instruments - Liabilities
Time Deposits	910,982	998,134
Securities Sold Under Agreements to Repurchase	450,907	469,293
Quoted Prices in Active Markets for Identical Assets or Liabilities (Level 1) | Fair Value
Financial Instruments - Assets
Held-to-Maturity: Fair Value	122,942	131,139
Loans	0	0
Financial Instruments - Liabilities
Time Deposits	0	0
Securities Sold Under Agreements to Repurchase	0	0
Significant Other Observable Inputs (Level 2) | Fair Value
Financial Instruments - Assets
Held-to-Maturity: Fair Value	4,048,320	4,515,480
Loans	0	0
Financial Instruments - Liabilities
Time Deposits	910,982	998,134
Securities Sold Under Agreements to Repurchase	450,907	469,293
Significant Other Unobservable Inputs (Level 3) | Fair Value
Financial Instruments - Assets
Held-to-Maturity: Fair Value	0	0
Loans	11,931,447	12,094,631
Financial Instruments - Liabilities
Time Deposits	0	0
Securities Sold Under Agreements to Repurchase	$ 0	$ 0