Renasant Corporation (Parent Company Only) Condensed Financial Information - Statements of Cash Flows (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Operating activities
Net income	$ 38,415	$ 37,446	$ 46,625	$ 45,110	$ 44,420	$ 31,964	$ 36,710	$ 33,826	$ 167,596	$ 146,920	$ 92,188
Adjustments to reconcile net income to net cash provided by operating activities:
(Increase) decrease in other assets									683	(11,849)	(1,139)
Increase (decrease) in other liabilities									(12,249)	(41,954)	(12,572)
Net cash provided by operating activities									163,623	82,112	207,042
Investing activities
Net cash (paid) received in acquisition										153,502	41,685
Other, net									917	0	0
Net cash (used in) provided by investing activities									(505,910)	(503,287)	69,661
Financing activities
Cash paid for dividends									(50,901)	(43,614)	(34,416)
Cash received on exercise of stock-based compensation									0	201	173
Repurchase of shares in connection with stock repurchase program									(62,944)	(7,062)	0
Repayment of long-term debt									(35,359)	(849)	(170,240)
Net cash provided by (used in) financing activities									188,106	708,833	(301,474)
Net (decrease) increase in cash and cash equivalents									(154,181)	287,658	(24,771)
Cash and cash equivalents at beginning of year				569,111				281,453	569,111	281,453	306,224
Cash and cash equivalents at end of year	414,930				569,111				414,930	569,111	281,453
Renasant Corporation
Operating activities
Net income									167,596	146,920	92,188
Adjustments to reconcile net income to net cash provided by operating activities:
Equity in undistributed net income of bank subsidiary									(46,684)	(103,619)	(65,970)
Amortization/depreciation/accretion									(76)	160	656
(Increase) decrease in other assets									(2,678)	3,381	(1,069)
Increase (decrease) in other liabilities									10,872	(171)	(2,291)
Net cash provided by operating activities									129,030	46,671	23,514
Investing activities
Sales and maturities of securities held to maturity and available for sale									42	1,052	1,555
Investment in subsidiaries									0	0	(25,000)
Net cash (paid) received in acquisition									0	(34,836)	4,834
Other, net									632	423	(54)
Net cash (used in) provided by investing activities									674	(33,361)	(18,665)
Financing activities
Cash paid for dividends									(50,901)	(43,614)	(34,416)
Cash received on exercise of stock-based compensation									0	201	173
Repurchase of shares in connection with stock repurchase program									(62,944)	(7,062)	0
Repayment of long-term debt									(30,973)	0	(10,310)
Other financing activities									0	(93)	310
Net cash provided by (used in) financing activities									(144,818)	(50,568)	(44,243)
Net (decrease) increase in cash and cash equivalents									(15,114)	(37,258)	(39,394)
Cash and cash equivalents at beginning of year				$ 44,581				$ 81,839	44,581	81,839	121,233
Cash and cash equivalents at end of year	$ 29,467				$ 44,581				$ 29,467	$ 44,581	$ 81,839