Regulatory Matters - Capital and Risk-based Capital and Leverage Ratios (Details) $ in Thousands	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)
Renasant Corporation
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Amount Included in Tier 1 Capital	$ 1,306,597	$ 1,262,588
Tier 1 Capital to Average Assets (Leverage) (percent)	0.0937	0.1037
Common Equity Tier One Capital to Risk - Weighted Assets, amount	$ 1,199,394	$ 1,156,828
Common Equity Tier One Capital to Risk - Weighted Assets (percent)	10.93%	11.12%
Tier 1 Capital to Risk -Weighted Assets, amount	$ 1,306,597	$ 1,262,588
Tier 1 Capital to Risk - Weighted Assets (percent)	0.1191	0.1214
Total Capital to Risk - Weighted Assets, amount	$ 1,653,694	$ 1,432,949
Total Capital to Risk - Weighted Assets (percent)	0.1507	0.1378
Renasant Bank
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Amount Included in Tier 1 Capital	$ 1,369,994	$ 1,331,809
Tier 1 Capital to Average Assets (Leverage) (percent)	0.0983	0.1095
Common Equity Tier One Capital to Risk - Weighted Assets, amount	$ 1,369,994	$ 1,331,809
Common Equity Tier One Capital to Risk - Weighted Assets (percent)	12.49%	12.81%
Tier 1 Capital to Risk -Weighted Assets, amount	$ 1,369,994	$ 1,331,809
Tier 1 Capital to Risk - Weighted Assets (percent)	0.1249	0.1281
Total Capital to Risk - Weighted Assets, amount	$ 1,504,985	$ 1,388,553
Total Capital to Risk - Weighted Assets (percent)	0.1373	0.1336