Regulatory Matters (Details) $ / shares in Units, shares in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2021 USD ($) $ / shares	Sep. 30, 2020 shares	Sep. 30, 2021 USD ($) $ / shares	Dec. 31, 2020 USD ($) $ / shares
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Preceding period of retained earnings used in calculation of dividend payable				2 years
Retained earnings		$ 1,748,491,000		$ 1,748,491,000	$ 1,407,723,000
Quarterly common stock dividend (in dollar per share) | $ / shares		$ 0.18		$ 0.18	$ 0.16
Depositary Shares | shares			9,000
Preferred Stock, Dividend Rate, Per-Dollar-Amount | $ / shares		$ 16.88
Preferred Stock, Dividend Per Depositary Share		$ 0.422
Pinnacle Financial
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Cash dividends paid to Pinnacle Financial by Pinnacle Bank				$ 66,500,000
Actual
Total capital to risk weighted assets		3,915,561,000		3,915,561,000	$ 3,678,405,000
Tier I capital to risk weighted assets		3,156,777,000		3,156,777,000	2,803,541,000
Common equity Tier 1 capital to risk weighted assets		2,939,528,000		2,939,528,000	2,586,292,000
Tier I capital to average assets	[1]	$ 3,156,777,000		$ 3,156,777,000	$ 2,803,541,000
Actual
Total capital to risk weighted assets (as percent)		0.140		0.140	0.143
Tier I capital to risk weighted assets (as percent)		0.113		0.113	0.109
Common equity Tier 1 capital to risk weighted assets		0.105		0.105	0.100
Tier I capital to average assets (as percent)	[1]	0.093		0.093	0.086
Minimum Capital Requirement
Total capital to risk weighted assets		$ 2,235,652,000		$ 2,235,652,000	$ 2,063,352,000
Tier I capital to risk weighted assets		1,676,739,000		1,676,739,000	1,547,514,000
Common equity Tier 1 capital to risk weighted assets		1,257,554,000		1,257,554,000	1,160,635,000
Tier I capital to average assets	[1]	$ 1,355,712,000		$ 1,355,712,000	$ 1,298,756,000
Minimum Capital Requirement
Total capital to risk weighted assets (as percent)		0.080		0.080	0.080
Tier I capital to risk weighted assets (as percent)		0.060		0.060	0.060
Common Equity Tier I capital to risk weighted assets (as percent)		0.045		0.045	0.045
Tier I capital to average assets (as percent)	[1]	0.040		0.040	0.040
Minimum To Be Well-Capitalized
Total capital to risk weighted assets		$ 2,794,565,000		$ 2,794,565,000	$ 2,579,190,000
Tier I capital to risk weighted assets		$ 2,235,652,000		$ 2,235,652,000	$ 2,063,352,000
Minimum To Be Well-Capitalized
Total capital to risk weighted assets (as percent)		0.100		0.100	0.100
Tier I capital to risk weighted assets (as percent)		0.080		0.080	0.080
Pinnacle Bank
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Retained earnings		$ 773,100,000		$ 773,100,000
Actual
Total capital to risk weighted assets		3,466,596,000		3,466,596,000	$ 3,259,538,000
Tier I capital to risk weighted assets		3,256,812,000		3,256,812,000	2,933,674,000
Common equity Tier 1 capital to risk weighted assets		3,256,689,000		3,256,689,000	2,933,551,000
Tier I capital to average assets	[1]	$ 3,256,812,000		$ 3,256,812,000	$ 2,933,674,000
Actual
Total capital to risk weighted assets (as percent)		0.125		0.125	0.127
Tier I capital to risk weighted assets (as percent)		0.117		0.117	0.114
Common equity Tier 1 capital to risk weighted assets		0.117		0.117	0.114
Tier I capital to average assets (as percent)	[1]	0.096		0.096	0.091
Minimum Capital Requirement
Total capital to risk weighted assets		$ 2,223,799,000		$ 2,223,799,000	$ 2,055,892,000
Tier I capital to risk weighted assets		1,667,849,000		1,667,849,000	1,541,919,000
Common equity Tier 1 capital to risk weighted assets		1,250,887,000		1,250,887,000	1,156,439,000
Tier I capital to average assets	[1]	$ 1,350,660,000		$ 1,350,660,000	$ 1,294,033,000
Minimum Capital Requirement
Total capital to risk weighted assets (as percent)		0.080		0.080	0.080
Tier I capital to risk weighted assets (as percent)		0.060		0.060	0.060
Common Equity Tier I capital to risk weighted assets (as percent)		0.045		0.045	0.045
Tier I capital to average assets (as percent)	[1]	0.040		0.040	0.040
Minimum To Be Well-Capitalized
Total capital to risk weighted assets		$ 2,779,749,000		$ 2,779,749,000	$ 2,569,865,000
Tier I capital to risk weighted assets		2,223,799,000		2,223,799,000	2,055,892,000
Common equity Tier 1 capital to risk weighted assets		1,806,837,000		1,806,837,000	1,670,412,000
Tier I capital to average assets	[1]	$ 1,688,325,000		$ 1,688,325,000	$ 1,617,541,000
Minimum To Be Well-Capitalized
Total capital to risk weighted assets (as percent)		0.100		0.100	0.100
Tier I capital to risk weighted assets (as percent)		0.080		0.080	0.080
Common Equity Tier I capital to risk weighted assets (as percent)		0.065		0.065	0.065
Tier I capital to average assets (as percent)	[1]	0.050		0.050	0.050

[1] (*) Average assets for the above calculations were based on the most recent quarter.