Quarterly Financial Data (unaudited) - Additional Information (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		12 Months Ended
	Dec. 31, 2018	Jun. 30, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Recoveries			$ 912	$ 3,150	$ 1,301
Charge-offs			3,463	15,651	7,137
Commercial, Financial and Agricultural [Member]
Recoveries			367	2,140	801
Charge-offs			$ 1,965	$ 14,655	$ 1,030
Loan Participations [Member] | Commercial, Financial and Agricultural [Member]
Recoveries	$ 1,800
Recovery, after-tax	$ 1,500
Effect on diluted earnings per share	$ 0.05	$ 0.34
Charge-offs		$ 12,700
Charge-off, after-tax		$ 10,100