Regulatory Matters - Capital and Risk-Based Capital and Leverage Ratios (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Renasant corporation
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Tier 1 capital to average assets (leverage) - amount	$ 1,239,814	$ 1,262,588
Tier 1 capital to average assets (leverage) - ratio	9.90%	10.37%
Common equity tier 1 capital to risk-weighted assets - amount	$ 1,133,444	$ 1,156,828
Common equity tier 1 capital to risk-weighted assets - ratio	10.63%	11.12%
Tier 1 capital to risk-weighted assets - amount	$ 1,239,814	$ 1,262,588
Tier 1 capital to risk-weighted assets - ratio	11.63%	12.14%
Total capital to risk-weighted assets - amount	$ 1,432,281	$ 1,432,949
Total capital to risk-weighted assets - ratio	13.44%	13.78%
Renasant bank
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Tier 1 capital to average assets (leverage) - amount	$ 1,308,943	$ 1,331,809
Tier 1 capital to average assets (leverage) - ratio	10.46%	10.95%
Common equity tier 1 capital to risk-weighted assets - amount	$ 1,308,943	$ 1,331,809
Common equity tier 1 capital to risk-weighted assets - ratio	12.28%	12.81%
Tier 1 capital to risk-weighted assets - amount	$ 1,308,943	$ 1,331,809
Tier 1 capital to risk-weighted assets - ratio	12.28%	12.81%
Total capital to risk-weighted assets - amount	$ 1,387,752	$ 1,388,553
Total capital to risk-weighted assets - ratio	13.02%	13.36%