Regulatory Matters - Capital and Risk-Based Capital and Leverage Ratios (Details) $ in Thousands	Mar. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)
Renasant corporation
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Tier 1 capital to average assets (leverage) - amount	$ 1,353,317	$ 1,306,597
Tier 1 capital to average assets (leverage) - ratio	0.0949	0.0937
Common equity tier 1 capital to risk-weighted assets - amount	$ 1,245,969	$ 1,199,394
Common equity tier 1 capital to risk-weighted assets - ratio	11.05%	10.93%
Tier 1 capital to risk-weighted assets - amount	$ 1,353,317	$ 1,306,597
Tier 1 capital to risk-weighted assets - ratio	0.1200	0.1191
Total capital to risk-weighted assets - amount	$ 1,701,667	$ 1,653,694
Total capital to risk-weighted assets - ratio	0.1509	0.1507
Renasant bank
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Tier 1 capital to average assets (leverage) - amount	$ 1,412,831	$ 1,369,994
Tier 1 capital to average assets (leverage) - ratio	0.0991	0.0983
Common equity tier 1 capital to risk-weighted assets - amount	$ 1,412,831	$ 1,369,994
Common equity tier 1 capital to risk-weighted assets - ratio	12.52%	12.49%
Tier 1 capital to risk-weighted assets - amount	$ 1,412,831	$ 1,369,994
Tier 1 capital to risk-weighted assets - ratio	0.1252	0.1249
Total capital to risk-weighted assets - amount	$ 1,548,990	$ 1,504,985
Total capital to risk-weighted assets - ratio	0.1372	0.1373