Renasant Corporation (Parent Company Only) Condensed Financial Information - Statements of Cash Flows (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Operating activities
Net income	$ 31,521	$ 29,992	$ 20,130	$ 2,008	$ 38,415	$ 37,446	$ 46,625	$ 45,110	$ 83,651	$ 167,596	$ 146,920
Adjustments to reconcile net income to net cash provided by operating activities:
(Increase) decrease in other assets									(59,224)	683	(11,849)
Increase (decrease) in other liabilities									27,077	(12,249)	(41,954)
Net cash provided by operating activities									82,242	163,623	82,112
Investing activities
Net cash paid in acquisition											153,502
Other, net									1,446	917	0
Net cash used in investing activities									(1,265,548)	(505,910)	(503,287)
Financing activities
Cash paid for dividends									(50,134)	(50,901)	(43,614)
Cash received on exercise of stock-based compensation									0	0	201
Repurchase of shares in connection with stock repurchase program									(24,569)	(62,944)	(7,062)
Repayment of long-term debt									(171)	(35,359)	(849)
Proceeds from long-term debt									98,266	150,000	0
Net cash provided by financing activities									1,401,579	188,106	708,833
Net increase (decrease) in cash and cash equivalents									218,273	(154,181)	287,658
Cash and cash equivalents at beginning of year				414,930				569,111	414,930	569,111	281,453
Cash and cash equivalents at end of year	633,203				414,930				633,203	414,930	569,111
Renasant Corporation
Operating activities
Net income									83,651	167,596	146,920
Adjustments to reconcile net income to net cash provided by operating activities:
Equity in undistributed net income of bank subsidiary									(13,322)	(46,684)	(103,619)
Amortization/depreciation/accretion									692	(76)	160
(Increase) decrease in other assets									(256)	(2,678)	3,381
Increase (decrease) in other liabilities									10,932	10,872	(171)
Net cash provided by operating activities									81,697	129,030	46,671
Investing activities
Purchases of securities held to maturity and available for sale									(6,104)	0	0
Sales and maturities of securities held to maturity and available for sale									541	42	1,052
Net cash paid in acquisition									0	0	(34,836)
Other, net									0	632	423
Net cash used in investing activities									(5,563)	674	(33,361)
Financing activities
Cash paid for dividends									(50,134)	(50,901)	(43,614)
Cash received on exercise of stock-based compensation									0	0	201
Repurchase of shares in connection with stock repurchase program									(24,569)	(62,944)	(7,062)
Repayment of long-term debt									0	(30,973)	0
Proceeds from long-term debt									98,266	0	0
Other financing activities									0	0	(93)
Net cash provided by financing activities									23,563	(144,818)	(50,568)
Net increase (decrease) in cash and cash equivalents									99,697	(15,114)	(37,258)
Cash and cash equivalents at beginning of year				$ 29,467				$ 44,581	29,467	44,581	81,839
Cash and cash equivalents at end of year	$ 129,164				$ 29,467				$ 129,164	$ 29,467	$ 44,581