Securities Available for Sale and Held to Maturity - Securities Held to Maturity by Credit Rating, as Determined by Moody's (Details) - USD ($) $ in Thousands		Dec. 31, 2021	Dec. 31, 2020
Schedule of Available For Sale and Held to Maturity Securities [Line Items]
Securities Held to Maturity Amortized Cost		$ 342,537	$ 538,072
Aaa [Member]
Schedule of Available For Sale and Held to Maturity Securities [Line Items]
Securities Held to Maturity Amortized Cost		335,208	511,488
Aaa1 to Aa3 [Member]
Schedule of Available For Sale and Held to Maturity Securities [Line Items]
Securities Held to Maturity Amortized Cost		5,007	22,528
Not Rated [Member]
Schedule of Available For Sale and Held to Maturity Securities [Line Items]
Securities Held to Maturity Amortized Cost	[1]	$ 2,322	$ 4,056

[1] Not rated securities primarily consist of Mississippi municipal general obligations.