Regulatory Matters - Capital and Risk-based Capital and Leverage Ratios (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Renasant Corporation
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Amount Included in Tier 1 Capital	$ 1,262,588	$ 1,188,412
Tier 1 Capital to Average Assets (Leverage) (percent)	10.37%	10.11%
Common Equity Tier One Capital to Risk - Weighted Assets, amount	$ 1,156,828	$ 1,085,751
Common Equity Tier One Capital to Risk - Weighted Assets (percent)	11.12%	11.05%
Tier 1 Capital to Risk -Weighted Assets, amount	$ 1,262,588	$ 1,188,412
Tier 1 Capital to Risk - Weighted Assets (percent)	12.14%	12.10%
Total Capital to Risk - Weighted Assets, amount	$ 1,432,949	$ 1,386,507
Total Capital to Risk - Weighted Assets (percent)	13.78%	14.12%
Renasant Bank
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Amount Included in Tier 1 Capital	$ 1,331,809	$ 1,276,976
Tier 1 Capital to Average Assets (Leverage) (percent)	10.95%	10.88%
Common Equity Tier One Capital to Risk - Weighted Assets, amount	$ 1,331,809	$ 1,276,976
Common Equity Tier One Capital to Risk - Weighted Assets (percent)	12.81%	13.02%
Tier 1 Capital to Risk -Weighted Assets, amount	$ 1,331,809	$ 1,276,976
Tier 1 Capital to Risk - Weighted Assets (percent)	12.81%	13.02%
Total Capital to Risk - Weighted Assets, amount	$ 1,388,553	$ 1,331,619
Total Capital to Risk - Weighted Assets (percent)	13.36%	13.58%